Segment Information (Total Assets) (Details) (USD $) In Millions, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014
Segment Reporting Information [Line Items]
Total assets	$ 919,790	$ 902,337
Retail
Segment Reporting Information [Line Items]
Total assets	363,783	359,188
Group, Voluntary & Worksite Benefits
Segment Reporting Information [Line Items]
Total assets	48,474	46,483
Corporate Benefit Funding
Segment Reporting Information [Line Items]
Total assets	236,925	228,543
Latin America
Segment Reporting Information [Line Items]
Total assets	72,074	72,259
Asia
Segment Reporting Information [Line Items]
Total assets	116,278	117,894
Europe, the Middle East and Africa
Segment Reporting Information [Line Items]
Total assets	27,991	29,217
Corporate & Other
Segment Reporting Information [Line Items]
Total assets	$ 54,265	$ 48,753