Here's the key to a happy retirement

This may surprise no one: If you retire with a decent amount of wealth, you'll be happier for it.

That's one finding of a new survey that interviewed 1,000 newly retired baby boomers with at least $100,000 in investable assets.

The study, conducted by Ameriprise Financial (AMP), polled boomers ages 60 to 73 who retired in the last five years to find out why they decided to retire. Half said they decided it was time to enjoy life or they didn't want to work any longer. About 17 percent said they had enough retirement savings to make the leap, and 16 percent said they lost their jobs or were pushed into retirement by their employers.

Few in the group regretted the decision to retire. Three in four boomers said they were "very satisfied" with their lives and that they were spending their days doing exactly what they had imagined. Nearly a third said there was nothing difficult about the move into retirement, and 43 percent said they were having more fun than they expected.

It all sounds rather idyllic, doesn't it? You can almost picture couples straight out of those financial advisor commercials, the ones who sail their boats across the sea or tend to their magnificent gardens.

But keep in mind that the survey interviewed newly retired boomers with at least $100,000 in investable assets. The picture is very different for the 40 percent of American households near retirement age with no retirement savings at all.

How do those Americans plan to spend retirement? They don't. About 37 percent of people in a 2013 Wells Fargo study said they don't expect to retire at all. Instead, they plan to "work until I'm too sick or die." And nearly half of those polled said they weren't confident they'd be able to save enough for a comfortable retirement.

Even those retirees with at least $100,000 in investable assets may not have enough to survive retirement. But this group certainly feels more confident. About three-quarters of them felt "in control" of their decision to retire, according to the Ameriprise survey, while more than half said they were very satisfied with their financial situation in retirement.

One in 10 of these retirees returned to some form of a job during retirement, but most said they didn't do it for the money. Instead, they found an interesting opportunity or wanted to keep their minds fresh.

The takeaway here? Start saving for retirement early. It could mean the difference between a life straight out of a commercial or a life spent mostly on the clock, worried about paying the bills.