That hope could be misplaced, if other data are to be believed: for instance, that millennials expect to work for only 15 years and save $445,687 for retirement, and they anticipate receiving an average of $1.06 million from inheritance—twice as much income as from their paychecks. That's from Personal Capital's Retirement Readiness Planner, compiled in October 2015.

The head-in-the-sand approach apparently works for some, with six percent of millennials saying that they don't ever look at the balances of their retirement savings accounts.

And men, surprisingly, are more emotional about their retirement balances than women—63 percent vs. 43 percent—with twice as many millennial men feeling hopeless about those balances than women (12 percent compared with 6 percent).

Maybe that has something to do with the fact that millennial men are also considerably more likely to say they'd pull money from those retirement accounts to pay for a big purchase, such as a vacation, boat, car, or wedding: 15 percent, compared with just 4 percent of women.

The ostriches among them aside, millennials are more than twice as likely than people aged 45 and older to say that if they were able to access their retirement savings account on their mobile device, they would check it daily (15 percent vs. 6 percent, respectively). That's probably good news for tech-heavy Personal Capital, founded in 2009, which combines financial technology with live financial advisors; the hybrid firm currently has $2.3 billion in assets under management.