Ninety-six percent of millennials feel "highly confident" about their benefits choices, compared to 66 percent of Generation Xers and 64 percent of baby boomers, according to research from The Guardian Life Insurance Company of America, an employee benefits provider.

The survey also shows that 80 percent of respondents spend less than two hours assessing their insurance benefits options, which includes group medical, dental, life and disability insurance, and only 32 percent of all respondents believe they regard open enrollment as a "careful review" of their benefits details and options.

Although 50 percent of millennials are more likely to say they carefully enrolled in available benefits options, compared to 30 percent of Generation Xers and 31 percent of baby boomers, millennials may be underinsured, the research finds. In fact, 78 percent of millennials are enrolled in available benefits, compared to their older colleagues at 92 percent.