Investments (Net Investment Income) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Net Investment Income [Line Items]
Less: Investment expenses	$ 281	$ 308	$ 862	$ 923
Subtotal	5,464	3,959	14,910	14,367
Securities Investment
Net Investment Income [Line Items]
Subtotal	5,213	4,964	15,141	15,355
Subtotal	4,932	4,656	14,279	14,432
Fixed maturity securities
Net Investment Income [Line Items]
Subtotal	3,583	3,525	10,801	10,738
Equity securities
Net Investment Income [Line Items]
Subtotal	35	36	105	102
Actively traded securities and FVO general account securities
Net Investment Income [Line Items]
Subtotal	25	(35)	41	4
Mortgage loans
Net Investment Income [Line Items]
Subtotal	806	786	2,464	2,317
Policy loans
Net Investment Income [Line Items]
Subtotal	148	147	444	450
Real estate and real estate joint ventures
Net Investment Income [Line Items]
Subtotal	210	233	516	767
Other limited partnership interests
Net Investment Income [Line Items]
Subtotal	263	216	429	681
Cash, cash equivalents and short-term investments
Net Investment Income [Line Items]
Subtotal	43	29	126	101
Operating joint ventures
Net Investment Income [Line Items]
Subtotal	5	(1)	28	15
Other
Net Investment Income [Line Items]
Subtotal	95	28	187	180
Consolidated Securitization Entities And Fair Value Option Contractholder-Directed Unit-Linked
Net Investment Income [Line Items]
Subtotal	532	(697)	631	(65)
FVO contractholder-directed unit-linked investments
Net Investment Income [Line Items]
Subtotal	529	(701)	623	(79)
Commercial mortgage loans | Consolidated Securitization Entities
Net Investment Income [Line Items]
Subtotal	3	4	8	13
Securities | Consolidated Securitization Entities
Net Investment Income [Line Items]
Subtotal	$ 0	$ 0	$ 0	$ 1