Investments (Net Investment Income) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
Net Investment Income [Line Items]
Less: Investment expenses	$ 302	$ 276
Subtotal	5,461	5,035
Securities Investment [Member]
Net Investment Income [Line Items]
Subtotal	5,082	5,224
Subtotal	4,780	4,948
Debt Securities [Member]
Net Investment Income [Line Items]
Subtotal	3,541	3,653
Equity securities
Net Investment Income [Line Items]
Subtotal	31	30
Actively traded securities and FVO general account securities [Member]
Net Investment Income [Line Items]
Subtotal	37	37
Changes in estimated fair value included in net investment income	6	11
Mortgage loans
Net Investment Income [Line Items]
Subtotal	730	709
Policy loans
Net Investment Income [Line Items]
Subtotal	152	157
Real estate and real estate joint ventures
Net Investment Income [Line Items]
Subtotal	211	217
Other limited partnership interests
Net Investment Income [Line Items]
Subtotal	215	329
Cash, cash equivalents and short-term investments
Net Investment Income [Line Items]
Subtotal	35	47
Operating joint ventures
Net Investment Income [Line Items]
Subtotal	8	0
Other
Net Investment Income [Line Items]
Subtotal	122	45
Consolidated Securitization Entities And Fair Value Option Contractholder-Directed Unit-Linked [Member]
Net Investment Income [Line Items]
Subtotal	681	87
FVO contractholder-directed unit-linked investments
Net Investment Income [Line Items]
Subtotal	677	65
Changes in estimated fair value included in net investment income	536	(41)
Commercial Loan [Member] | Consolidated Securitization Entities
Net Investment Income [Line Items]
Subtotal	$ 4	$ 22