Investments (Net Investment Income) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Net Investment Income [Line Items]
Less: Investment expenses	$ 285	$ 313	$ 581	$ 615
Subtotal	4,887	4,947	9,446	10,408
Securities Investment
Net Investment Income [Line Items]
Subtotal	4,979	5,309	9,928	10,391
Subtotal	4,694	4,996	9,347	9,776
Fixed maturity securities
Net Investment Income [Line Items]
Subtotal	3,564	3,672	7,218	7,213
Equity securities
Net Investment Income [Line Items]
Subtotal	33	35	70	66
Actively traded securities and FVO general account securities
Net Investment Income [Line Items]
Subtotal	10	2	16	39
Changes in estimated fair value included in net investment income	(1)	(38)	(1)	(40)
Mortgage loans
Net Investment Income [Line Items]
Subtotal	851	801	1,658	1,531
Policy loans
Net Investment Income [Line Items]
Subtotal	147	151	296	303
Real estate and real estate joint ventures
Net Investment Income [Line Items]
Subtotal	149	323	306	534
Other limited partnership interests
Net Investment Income [Line Items]
Subtotal	120	250	166	465
Cash, cash equivalents and short-term investments
Net Investment Income [Line Items]
Subtotal	43	37	83	72
Operating joint ventures
Net Investment Income [Line Items]
Subtotal	11	8	23	16
Other
Net Investment Income [Line Items]
Subtotal	51	30	92	152
Consolidated Securitization Entities And Fair Value Option Contractholder-Directed Unit-Linked
Net Investment Income [Line Items]
Subtotal	193	(49)	99	632
FVO contractholder-directed unit-linked investments
Net Investment Income [Line Items]
Subtotal	191	(55)	94	622
Changes in estimated fair value included in net investment income	80	(288)	(120)	261
Commercial mortgage loans | Consolidated Securitization Entities
Net Investment Income [Line Items]
Subtotal	2	5	5	9
Securities | Consolidated Securitization Entities
Net Investment Income [Line Items]
Subtotal	$ 0	$ 1	$ 0	$ 1