Most Americans have lofty dreams for the future, but too many aren't prepared to bring them to life.

One-quarter of millennials who expect to retire between ages 66 and 75 have no retirement savings account, according to an INSIDER and Morning Consult survey. And about 31% of millennials who expect to own a home aren't saving for one.

Of the 4,400 Americans polled, 353 identified as Gen Zers (ages 18 to 21), 1,207 identified as millennials (ages 22 to 37), 1,131 identified as Gen Xers (ages 38 to 53), 1,472 identified as baby boomers (ages 54 to 72), and 237 respondents did not select a generation. The margin of error was plus or minus 1 percentage point.

But it's not just millennials whose goals don't align with their habits. Gen Xers, the closest generation to retirement age behind baby boomers, are largely unprepared to leave work one day. About half of Gen X respondents said they expected to retire before age 75 — 23% said between 56 and 65, and 28% said between 66 and 75.

And yet 47% of the Gen Xers said they had no money saved in a retirement account, almost equal to the share of those who said they do. About 48% of the savers have under $50,000, the survey found.

Meanwhile, 10% of Gen Xers said they don't expect to retire at all — the highest share of any generation — and 19% didn't have an opinion.

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These findings underscore a recent MetLife report, which found that 55% of Gen Xers said they were feeling either significantly or somewhat behind on their retirement-savings timeline and that 48% of Gen Xers were living paycheck to paycheck.

According the Morning Consult survey, of the 52% of millennials without a retirement savings account, 46% still expect to retire between 56 and 75, and 12% expect to retire early, before age 55. Looking at those with savings, nearly half of millennials said they had under $15,000.

Financial experts say retirement accounts are one of the best tools for saving and investing. The benefits of contributing to a tax-deferred IRA or 401(k) cannot be overstated. Contributions are taken pretax, so the money has greater potential for compound growth. And some employers will match contributions, which is essentially free money. The earlier you start saving, the greater the difference in your savings come retirement.

Read More: More than a third of millennials earning at least $100,000 a year consider themselves middle class

Millennials' and Gen Xers' savings habits and goals are also disjointed when it comes to homeownership, though less so than retirement. While 8% of millennials and 23% of Gen X respondents expect to never own a home, 70% and 50% indicated they would like to one day. However, just 40% of those millennials and half of those Gen Xers are actually saving to buy.

About 12% of baby boomers who don't own already also want to purchase a home one day but aren't saving right now. Interestingly, almost a greater share of Gen Zers (35%) are saving for a home than Gen Xers and baby boomers combined (37%). Given that this data is self-reported, let's see how those numbers change once Sallie Mae comes knocking.