But they still expect to retire at age 69, despite having already hit an average age of 64. To hit the total they think they need, they'll have to come up with a yearly savings total between now and then of about $142,357.

Yet 48 percent of boomers think they'll be comfortable in retirement as long as they're careful with their spending, and 21 percent believe they will have enough saved to lead the life they desire.

Among the more realistic boomers, 22 percent say they'll struggle to have enough and 10 percent don't think they will ever be able to retire.

Then there are the GenXers, who started saving at an average age of 29. For some reason they think they'll need less than boomers—just $980,466 on average—but have only hit 17 percent of their goal, with an average saved of just $166,328.

That's especially since 66 percent of those who participate in a company-sponsored defined contribution plan say that in addition to what they're saving at work, Social Security will be their primary source of funding for income in retirement—yet 42 percent of plan participants don't believe the benefits will still be available when they retire.

They too have an optimistic view of their retirement age—expecting to leave the job at age 64—and are an average of 45 presently. To meet their goal—lower than boomers, but still hefty—they'll have to come up with $42,849 a year till they hit that magic age.

Still, 37 percent of Gen X members think they'll have a comfy retirement if they keep a close eye on the purse strings, while 18 percent think they'll have enough saved to have the life they desire in retirement.

But 23 percent of their more realistic peers say they'll struggle to have enough, while 23 percent don't think they'll ever be able to retire.

What's holding all these folks back from saving more? Plenty, says the survey:

• 65 percent cite daily living expenses
• general debt,  43 percent
• housing costs,  43 percent
• health care costs,  32 percent

Then, of course, there are the 25 percent who are the grasshoppers of the bunch, rather than the ants, who say they'd rather spend money to enjoy life now.

For millennials, these are the savings obstacles people cite:

• daily expenses, 61 percent
• general debt, 47 percent
• housing costs, 40 percent
• education costs and student loans, 28 percent
• health care costs, 24 percent

And then there are the 27 percent who are, voluntarily or not, self-saboteurs, who have taken a withdrawal from their company DC plan. Life has caught up with these folks in the form of the need to pay down debt (38 percent); health care expenses (25 percent); purchase of a home (22 percent); loss of a job (17 percent); a medical emergency (15 percent); home repairs/maintenance (12 percent); a major expense like a vacation or wedding (12 percent); and college tuition (10 percent).

READ MORE:

Gulf in retirement preparedness mirrors gulf in behaviors

Race, ethnicity play huge role in retirement preparedness

5 retirement preparedness numbers for employers