Fair Value (Table of reconciliation for assets and liabilities measured at fair value on a recurring basis using significant unobservable inputs) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, Beginning, Assets	$ 1,231	$ 1,453	$ 1,303	$ 1,393
Net realized investment gains (losses) and net change in unrealized appreciation (depreciation) included in net income (loss)	5		13	(5)
Net change in unrealized appreciation (depreciation) included in other comprehensive income (loss)	(7)	(21)	58	(13)
Purchases	128	77	579	685
Sales		(6)	(373)	(324)
Settlements	(67)	(80)	(233)	(195)
Transfers into Level 3	42	17	97	73
Transfers out of Level 3	(77)	(69)	(189)	(243)
Balance, Ending, Assets	1,255	1,371	1,255	1,371
Unrealized gains (losses) on Level 3 assets and liabilities held at balance sheet date recognized in net income (loss)	1	(4)	2	(30)
Fixed maturity securities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, Beginning, Assets	1,143	1,347	1,203	1,251
Net realized investment gains (losses) and net change in unrealized appreciation (depreciation) included in net income (loss)	4	(1)	(13)	3
Net change in unrealized appreciation (depreciation) included in other comprehensive income (loss)	(6)	(23)	63	(15)
Purchases	112	77	563	685
Sales		(6)	(365)	(317)
Settlements	(66)	(76)	(208)	(172)
Transfers into Level 3	42	17	97	73
Transfers out of Level 3	(77)	(69)	(188)	(242)
Balance, Ending, Assets	1,152	1,266	1,152	1,266
Unrealized gains (losses) on Level 3 assets and liabilities held at balance sheet date recognized in net income (loss)		(2)	(1)	(7)
Corporate and other bonds [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, Beginning, Assets	194	202	204	219
Net realized investment gains (losses) and net change in unrealized appreciation (depreciation) included in net income (loss)		1	2	2
Net change in unrealized appreciation (depreciation) included in other comprehensive income (loss)	(1)			(1)
Purchases	4	6	30	129
Sales		(6)	(10)	(96)
Settlements	(3)	(8)	(13)	(34)
Transfers into Level 3		17	8	43
Transfers out of Level 3	(21)	(1)	(48)	(51)
Balance, Ending, Assets	173	211	173	211
Unrealized gains (losses) on Level 3 assets and liabilities held at balance sheet date recognized in net income (loss)				(2)
States, municipalities and political subdivisions [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, Beginning, Assets	79	140	71	96
Net realized investment gains (losses) and net change in unrealized appreciation (depreciation) included in net income (loss)			1	(3)
Net change in unrealized appreciation (depreciation) included in other comprehensive income (loss)	1	(3)	3	1
Purchases			1	122
Sales			(10)	(79)
Settlements		(15)		(20)
Transfers into Level 3			14	5
Transfers out of Level 3		(27)		(27)
Balance, Ending, Assets	80	95	80	95
Unrealized gains (losses) on Level 3 assets and liabilities held at balance sheet date recognized in net income (loss)
Residential mortgage-backed [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, Beginning, Assets	185	428	331	413
Net realized investment gains (losses) and net change in unrealized appreciation (depreciation) included in net income (loss)	1		(22)	2
Net change in unrealized appreciation (depreciation) included in other comprehensive income (loss)		(20)	62	(21)
Purchases		5	47	116
Sales			(174)	(10)
Settlements	(17)	(21)	(57)	(53)
Transfers into Level 3	11		32	4
Transfers out of Level 3	(20)	(22)	(59)	(81)
Balance, Ending, Assets	160	370	160	370
Unrealized gains (losses) on Level 3 assets and liabilities held at balance sheet date recognized in net income (loss)		(1)		(3)
Commercial Mortgage Backed Securities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, Beginning, Assets	59	165	151	129
Net realized investment gains (losses) and net change in unrealized appreciation (depreciation) included in net income (loss)	2	(1)	4
Net change in unrealized appreciation (depreciation) included in other comprehensive income (loss)	(2)	(2)	(2)	7
Purchases	28	10	28	88
Sales			(60)
Settlements	(21)	(1)	(23)	(10)
Transfers into Level 3	31		43	21
Transfers out of Level 3		(14)	(44)	(78)
Balance, Ending, Assets	97	157	97	157
Unrealized gains (losses) on Level 3 assets and liabilities held at balance sheet date recognized in net income (loss)
Other asset-backed [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, Beginning, Assets	626	387	446	368
Net realized investment gains (losses) and net change in unrealized appreciation (depreciation) included in net income (loss)	1		2	3
Net change in unrealized appreciation (depreciation) included in other comprehensive income (loss)	(4)	1		(1)
Purchases	80	56	457	230
Sales			(111)	(132)
Settlements	(25)	(6)	(115)	(30)
Transfers into Level 3
Transfers out of Level 3	(36)	(5)	(37)	(5)
Balance, Ending, Assets	642	433	642	433
Unrealized gains (losses) on Level 3 assets and liabilities held at balance sheet date recognized in net income (loss)		(1)	(1)	(2)
Total asset-backed [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, Beginning, Assets	870	980	928	910
Net realized investment gains (losses) and net change in unrealized appreciation (depreciation) included in net income (loss)	4	(1)	(16)	5
Net change in unrealized appreciation (depreciation) included in other comprehensive income (loss)	(6)	(21)	60	(15)
Purchases	108	71	532	434
Sales			(345)	(142)
Settlements	(63)	(28)	(195)	(93)
Transfers into Level 3	42		75	25
Transfers out of Level 3	(56)	(41)	(140)	(164)
Balance, Ending, Assets	899	960	899	960
Unrealized gains (losses) on Level 3 assets and liabilities held at balance sheet date recognized in net income (loss)		(2)	(1)	(5)
Redeemable preferred stock [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, Beginning, Assets		25		26
Net realized investment gains (losses) and net change in unrealized appreciation (depreciation) included in net income (loss)		(1)		(1)
Net change in unrealized appreciation (depreciation) included in other comprehensive income (loss)		1
Purchases
Sales
Settlements		(25)		(25)
Transfers into Level 3
Transfers out of Level 3
Balance, Ending, Assets
Unrealized gains (losses) on Level 3 assets and liabilities held at balance sheet date recognized in net income (loss)
Equity securities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, Beginning, Assets	2	13	11	34
Net realized investment gains (losses) and net change in unrealized appreciation (depreciation) included in net income (loss)		(2)	3	(22)
Net change in unrealized appreciation (depreciation) included in other comprehensive income (loss)	(1)	2	(5)	2
Purchases	16		16
Sales			(8)
Settlements
Transfers into Level 3
Transfers out of Level 3				(1)
Balance, Ending, Assets	17	13	17	13
Unrealized gains (losses) on Level 3 assets and liabilities held at balance sheet date recognized in net income (loss)		(2)		(22)
Other invested assets, including derivatives, net [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, Beginning, Assets
Net realized investment gains (losses) and net change in unrealized appreciation (depreciation) included in net income (loss)
Net change in unrealized appreciation (depreciation) included in other comprehensive income (loss)
Purchases
Sales				(1)
Settlements				1
Transfers into Level 3
Transfers out of Level 3
Balance, Ending, Assets
Unrealized gains (losses) on Level 3 assets and liabilities held at balance sheet date recognized in net income (loss)
Short-term investments [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, Beginning, Assets				6
Net realized investment gains (losses) and net change in unrealized appreciation (depreciation) included in net income (loss)
Net change in unrealized appreciation (depreciation) included in other comprehensive income (loss)
Purchases
Sales				(6)
Settlements
Transfers into Level 3
Transfers out of Level 3
Balance, Ending, Assets
Unrealized gains (losses) on Level 3 assets and liabilities held at balance sheet date recognized in net income (loss)
Life settlement contracts, included in Other assets [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, Beginning, Assets	86	91	88	100
Net realized investment gains (losses) and net change in unrealized appreciation (depreciation) included in net income (loss)	1	3	23	14
Net change in unrealized appreciation (depreciation) included in other comprehensive income (loss)
Purchases
Sales
Settlements	(1)	(4)	(25)	(24)
Transfers into Level 3
Transfers out of Level 3
Balance, Ending, Assets	86	90	86	90
Unrealized gains (losses) on Level 3 assets and liabilities held at balance sheet date recognized in net income (loss)	1		3	(1)
Separate account business [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, Beginning, Assets		2	1	2
Net realized investment gains (losses) and net change in unrealized appreciation (depreciation) included in net income (loss)
Net change in unrealized appreciation (depreciation) included in other comprehensive income (loss)
Purchases
Sales
Settlements
Transfers into Level 3
Transfers out of Level 3			(1)
Balance, Ending, Assets		2		2
Unrealized gains (losses) on Level 3 assets and liabilities held at balance sheet date recognized in net income (loss)