Segment Information (Total Assets) (Details) - USD ($) $ in Millions	Mar. 31, 2016	Dec. 31, 2015
Segment Reporting Information [Line Items]
Total assets	$ 917,428	$ 877,933
Retail
Segment Reporting Information [Line Items]
Total assets	354,705	347,257
Group, Voluntary & Worksite Benefits
Segment Reporting Information [Line Items]
Total assets	49,950	46,476
Corporate Benefit Funding
Segment Reporting Information [Line Items]
Total assets	231,484	225,015
Latin America
Segment Reporting Information [Line Items]
Total assets	68,949	65,266
Asia
Segment Reporting Information [Line Items]
Total assets	122,187	113,895
EMEA
Segment Reporting Information [Line Items]
Total assets	27,720	26,767
Corporate & Other
Segment Reporting Information [Line Items]
Total assets	$ 62,433	$ 53,257