Segment Information (Total Assets) (Details) - USD ($) $ in Millions	Jun. 30, 2016	Dec. 31, 2015
Segment Reporting Information [Line Items]
Total assets	$ 942,567	$ 877,933
Retail
Segment Reporting Information [Line Items]
Total assets	364,611	347,257
Group, Voluntary & Worksite Benefits
Segment Reporting Information [Line Items]
Total assets	51,721	46,476
Corporate Benefit Funding
Segment Reporting Information [Line Items]
Total assets	236,311	225,015
Latin America
Segment Reporting Information [Line Items]
Total assets	68,971	65,266
Asia
Segment Reporting Information [Line Items]
Total assets	131,537	113,895
EMEA
Segment Reporting Information [Line Items]
Total assets	27,007	26,767
Corporate & Other
Segment Reporting Information [Line Items]
Total assets	$ 62,409	$ 53,257