Rex Tillerson admits he was an unconventional choice for secretary of state. He had no prior government experience, but as CEO of Exxon-Mobil, he had crisscrossed the globe striking deals with foreign leaders. Secretary Tillerson - a man who still considers himself a Boy Scout and follows what he calls "the Code of the West" - is fiercely private and has shied away from interviews. But he agreed to do a rare, wide-ranging one with us.

With the Olympics underway and North Korea very much on his mind, he talked to us about what may be the toughest deal he will ever work on.

Secretary of State Rex Tillerson CBS News

Margaret Brennan: In his New Year's Day speech Kim Jong Un said the entire area of the U.S. mainland is within our nuclear strike range. That's gotta make you nervous.

Rex Tillerson: It does make us nervous. It-- it also-- it also stiffens our resolve. That kind of a threat to the American people by a regime like this is not acceptable. And the president's meeting his responsibilities as commander in chief of asking our military, Secretary Mattis at the Defense Department, to ensure we are prepared for anything.

"We're not using a carrot to convince them to talk. We're using large sticks."

Margaret Brennan: And those military options are there in case you fail.

Rex Tillerson: In case I fail. I say to my Chinese counterpart, "You and I fail these people get to fight. That's not what we want."

Margaret Brennan: But you are willing to work with and potentially negotiate with Kim Jong Un.

Rex Tillerson: Well, that's who we will have to work with to achieve this diplomatically. What we have to determine now is are we even ready to start? Are they ready to start? And if they're not, we'll just keep the pressure campaign underway and we will increase that pressure. And we are doing that every month. There are new sanctions rolled out. The world wants North Korea to change.

Margaret Brennan: Well, there's some questions about how badly China wants them to change. You've really needed their help to put economic pressure on Kim Jong Un. What reassurances have you given to China so that they actually follow through?

Rex Tillerson: What I think-- we got a common understanding with China is that North Korea represents a serious threat to China as well. And we've been very clear with them that they are going to have an important role to play once we get to the negotiating table.

Margaret Brennan: So I-- I hear you saying there-- these wouldn't be one on one talks. China would be at the table.

Rex Tillerson: Early on they might be one on one discussions for the U.S. first and North Korea to determine is there a reason to begin to put the construct for negotiations in place.

Margaret Brennan: What is the carrot that you're dangling for North Korea to convince them to talk?

Rex Tillerson: We're not using a carrot to convince them to talk. We're using large sticks. And that is what they need to understand. This pressure campaign is putting-- is having its bite on North Korea, its revenue streams. It's having a bite on its military programs.

Margaret Brennan: But to say full denuclearization, why would they agree to give up something they've already got that they think is an insurance policy?

Rex Tillerson: Because it buys them nothing. It buys them more of being the hermit kingdom, isolated, isolated from the world diplomatically, isolated from the world economically.

Margaret Brennan: Senator Bob Corker, chairman of Senate Foreign Relations Committee said "Every one of us should pray Rex Tillerson and Jim Mattis are successful over the course of the next eight to ten months, diplomatically, or our nation is going to be facing one of the greatest military decisions that we face." Eight to ten months. That's how much time you have to get this done?

Rex Tillerson: I'm gonna use all the time available to me our diplomatic efforts will continue until that first bomb drops. My job is to never have a reason for the first bomb to drop And we don't know precisely how much time is left on the clock.

Contributor Margaret Brennan interviews Secretary of State Rex Tillerson CBS News

Margaret Brennan: You seem to have convinced the president that diplomacy is the way to go on this. But it wasn't always so clear. Back in October, you said you were working to get a dialogue going with the North Koreans and the president tweeted, "Rex, stop wasting your time trying to negotiate with little rocket man." Have you asked him not to call him little rocket man? Is that a diplomatic term?

Rex Tillerson: The president's going to-- the president's gonna communicate the way he communicates. My job as chief diplomat is to ensure that the North Koreans know we keep our channels open, I'm listening. I'm not sending a lotta messages back 'cause there's nothing to say to them at this point. So I'm listening for you to tell me you're ready to talk.

Margaret Brennan: How will you know?

Rex Tillerson: They will tell me. They will tell me.

Margaret Brennan: That explicitly?

Rex Tillerson: We-- we receive messages from them And I think it will be very explicit as to how we want to have that first conversation.

As we saw during a meeting with top aides about the crisis in Yemen, the whole world is now his portfolio, but Rex Wayne Tillerson comes from a family of modest means in North Texas. He was named after actors Rex Allen and John Wayne, because his parents loved Westerns.

Margaret Brennan: We actually have a photo of you back in your Boy Scout uniform. I understand you rose to Eagle Scout?

Rex Tillerson: Yes.

Margaret Brennan: So how old were you here?

Rex Tillerson: I think I was 14 when that was taken.

Margaret Brennan: You look very proud.

Rex Tillerson: I am very proud. And was very proud. I still am.

Margaret Brennan: I can tell-- I mean, Boy Scouts, you reference it a fair amount. That played a big, formative role in your life.

Rex Tillerson: It really shaped who I am.

Margaret Brennan: You still think of yourself as a Boy Scout?

Rex Tillerson: Yes.

Margaret Brennan: Really?

Rex Tillerson: Absolutely.

Margaret Brennan: You don't get to be the CEO of Exxon Mobile as a Boy Scout.

Rex Tillerson: I did.

Margaret Brennan: You talked a lot about something that you call the Code of the West. What does that mean?

Rex Tillerson: Well, you know the Code of the West, as the West was unfolding there wasn't a lot of law enforcement. And people basically relied upon each other's word. And "My word is my bond." And I've used that throughout my life as well, even at Exxon Mobil. I would sit down with the head of state for that country or the CEO of that company and we'd look each other in the eye. And I'd say, all I need to know is that you're gonna live up to your side of this deal. And I give you my word I'll live up to my side of this deal. And then a lotta the Code of the West was people were very loyal to their organizations. And the phrase, "Riding for the brand" is a phrase that's always stuck with me that--

Margaret Brennan: Riding for the brand?

Rex Tillerson: Riding for the brand. When a cowboy signed on to a ranch or-- or to that organization, he was committed to that organization.

Margaret Brennan: And what is the brand for you now?

Rex Tillerson: The State Department of the United States government. The American people are my brand.

Tillerson and friends at his Texas ranch in 2017. Rex Tillerson

Margaret Brennan: So one leader you hadn't met before December of 2016 was Donald Trump. Tell me what that first encounter was like.

Rex Tillerson: We met in his office in Trump Tower. And-- he just began by askin' me, you know, "I want you to just kinda talk about how-- how you see the world." So we just-- we walked around the world for about an hour. And then after that-- He kinda went into a little bit of a sales pitch with me and said, "I want you to be my secretary of state." And I was stunned.

Margaret Brennan: You didn't know it was a job interview?

Rex Tillerson: No, I didn't. I didn't. I-- I thought it was just-- I was goin' up just to talk to him and share with him, which I've done with previous presidents. I did with President Obama, I did with President Bush. So I really thought that's all it was.

Margaret Brennan: Do you have any sense of what you were getting yourself into?

Rex Tillerson: By and large-- I did.

"You know, the only person that knows whether I'm resigning or not is me."

Margaret Brennan: You've won some policy arguments. When it came to keeping troops in Afghanistan. You prevented the president, in some ways, from tearing up the Iran nuclear deal, like you said he was going to do. You lost a few arguments too. The Paris Climate Agreement, the president exited. The Trans-Pacific Trade Partnership, you cautioned against ripping up a deal America had committed to, and you cautioned against moving the U.S. embassy to Jerusalem on the timeline they laid out. Do you think that's a fair accounting of your record?

Rex Tillerson: I think the American people have won with the decisions the president has taken. And it's not about agreeing or disagreeing. Because he's-- he's the decision maker.

Margaret Brennan: Tell me what it's like to work in an administration where the U.S. has walked away, or threatened to walk away from a number of commitments. That has to be hard for someone who believes in the Code of the West.

Rex Tillerson: Well some of those, I think it's important to keep in mind what the level of commitment was. We have agreements that the Congress never had the opportunity to weigh in on. And so President Trump was elected by the American people, and many of these were issues that he ran on.

In the past year, Tillerson spent a lot of time denying that he was being outflanked by others in the president's inner circle, and that he was either going to resign or be fired after reports he called the president "a moron."

Margaret Brennan: Why didn't you deny calling the president a moron?

Rex Tillerson: You know, that's a really old question.

Margaret Brennan: You understand that by not answering the question, some people thought you were confirming the story.

Rex Tillerson: I think I've answered the question.

Margaret Brennan: You think you answered the question.

Rex Tillerson: I've answered the question.

Margaret Brennan: Did you call the president a moron?

Rex Tillerson: I'm not gonna dignify the question. We got so many bigger issues that we could be talking about. I'm not from this town. I understand this town likes to talk about a lot of things that are really not important.

Margaret Brennan: Do you think you have enemies in this town?

Rex Tillerson: I don't know.

Margaret Brennan: Where do you think those reports came from? That you were resigning, or being fired?

Rex Tillerson: I-- I-- I have no idea where they come from. I really don't. And I don't give it much thought.

Margaret Brennan: I mean, you walk into ministry meetings and reporters are shouting, "Sir, when are you resigning?"

Rex Tillerson: I never hear those questions. You know, the only person that knows whether I'm resigning or not is me.

Margaret Brennan: So one of the other challenges that you have here-- is sometimes the president's message doesn't jive with your own. I think you'd acknowledge that.

Rex Tillerson: Well, as I said, the president communicates in his own style, his own way, his own words. And from time to time I will ask him, "Are you changin' the policy? Because if we are, obviously I need to know, and everyone needs to know."

Margaret Brennan: Well you would've thought he'd talk to you about changing the policy before he tweeted.

Rex Tillerson: And-- and to finish the thought, that has never happened. Every time I've talked to him he says, "No, the policy hasn't changed." And I say let-- then I'm good. That's all I need to know.

Within the ranks of the State Department, there have been complaints Secretary Tillerson is dismantling American diplomacy by embracing major budget cuts, and being slow to fill crucial jobs.

Margaret Brennan: There are 41 embassies without confirmed ambassadors and that's even in places where there are crises. No ambassador in South Korea, Saudi Arabia, in Turkey. How do you explain that?

Rex Tillerson: Well, there's been no dismantling at all of the State Department. We've got terrific-- people, both foreign service officers, civil servants, that have stepped into those roles around the world--

Margaret Brennan: On an interim--

Rex Tillerson: --and have stepped in--

Margaret Brennan: --basis.

Rex Tillerson: --here. It is an interim basis. So clearly, it is not with the same kind of support that I wish everyone had. But our foreign policy objectives continue to be met.

Margaret Brennan: But some of these don't even have nominees. I mean 41 embassies without ambassadors in them.

Rex Tillerson: Well, some of these are in the process. It's not a question of people being…are neglecting the importance of it. It's just the nature of the process itself.

"I'm here to serve my country. I committed to this president. My word is my bond."

Margaret Brennan: You've said you had a very close relationship with Vladimir Putin. You've done huge deals with him. Photos of you toasting him with champagne. And all that closeness raised eyebrows It even inspired a Saturday Night Live skit. Did you ever see that skit?

Rex Tillerson: I did. My kids pointed me to it.

Margaret Brennan: Did you laugh?

Rex Tillerson: Absolutely. Absolutely. I laughed out loud.

Margaret Brennan: What-- it-- it made light though of-- of this concern that you have-- a friendship with Vladimir Putin and that because of that you and the president aren't going to hold him to account.

Rex Tillerson: The relationship that I had with President Putin spans 18 years now It was always about What could I do to be successful on behalf of my shareholders, how Russia could succeed.

Margaret Brennan: How different was it walking into the Kremlin as secretary of state?

Rex Tillerson: It was different-- because-- and I had to think very, very h-- carefully about that, And the only thing I said to him was "Mr. President, same man, different hat."

Margaret Brennan: But the dynamic changed.

Rex Tillerson: The dynamic changed because the issues were different. What he is representing is different than what I now represent. And I-- and I said to him, "I now represent the American people." And-- and I think it was important that that be said right up front. And he clearly got, I mean, he clearly understood that as well.

Margaret Brennan: But since you're secretary of state now you've accused him of violating nuclear arms control agreements, of cheating on North Korea sanctions, letting Assad continue now to use chlorine gas chemical weapons on civilians. He doesn't seem to be particularly concerned about the warnings you're giving him.

Rex Tillerson: Well, I don't know. We'll see if he's concerned or not.

Margaret Brennan: There were six chlorine gas attacks in the past 30 days.

Rex Tillerson: That's correct. And we have called them out for the fact that Russia has special responsibilities, in our view, because of commitments they made, to destroy chemical weapons and ensure they knew that there were none.

Margaret Brennan: That sounds a lot like the last administration. That doesn't sound very different.

Rex Tillerson: Well, when it comes to killing people with chemical weapons It shouldn't look any different. I think the only difference is the consequences for it. And President Trump has already demonstrated there will be consequences.

Margaret Brennan: Does that mean military action is still on the table for chlorine gas attacks?

Rex Tillerson: As it was in April last year, we are serious about our demands that chemical weapons not become regularized or normalized as a-- as a weapon in any conflict.

Margaret Brennan: Why not implement the sanctions that Congress overwhelmingly says they wanna see put on Russia?

Rex Tillerson: We have and we are we've taken steps that have already prevented a number of Russian military sales as a result of the legislation. And we are evaluating additional individuals for-- for-- possible sanctioning.

Rex Tillerson speaks with contributor Margaret Brennan Kylie Atwood

Near the end of our interview, we were interrupted by a phone call from the president. Afterward, the secretary took us out for a brief stroll on his terrace before heading to the White House.

Margaret Brennan: How often do you talk to the president?

Rex Tillerson: We typically'll try to talk every day, even if it's only for a few minutes. A lotta times, I'll call from the-- the road when I'm on a trip just to let him know how it's going.

Rex Tillerson enjoys the view from the top of the State Department, he seems to be one of the few people in Washington not surprised he's still here.

Margaret Brennan: If I believe the press reports that came out about you in the past year, you would not be sitting here talking to me as the secretary of state. It seems like reports of your political death were premature?

Rex Tillerson: Well I hope with this little bit of exchange we've had you understand the man better. That's why I'm still here. Those things don't bother me. I'm here to serve my country. I committed to this president. My word is my bond. I ride for this brand. That's why I'm here. And nothin' anybody else says is gonna change that.

Produced by Andy Court, Evie Salomon and Kylie Atwood