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
	Mar. 31, 2014	Mar. 31, 2013
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, Beginning, Assets	$ 1,303	$ 1,393
Net realized investment gains (losses) and net change in unrealized appreciation (depreciation) included in net income (loss)	17	(4)
Net change in unrealized appreciation (depreciation) included in other comprehensive income (loss)	12	9
Purchases	178	465
Sales	(95)	(165)
Settlements	(110)	(65)
Transfers into Level 3	38	26
Transfers out of Level 3	(55)	(59)
Balance, Ending, Assets	1,288	1,600
Unrealized gains (losses) on Level 3 assets and liabilities held at balance sheet date recognized in net income (loss)	1	(16)
Fixed maturity securities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, Beginning, Assets	1,203	1,251
Net realized investment gains (losses) and net change in unrealized appreciation (depreciation) included in net income (loss)	4	4
Net change in unrealized appreciation (depreciation) included in other comprehensive income (loss)	16	8
Purchases	178	465
Sales	(87)	(163)
Settlements	(99)	(53)
Transfers into Level 3	38	26
Transfers out of Level 3	(54)	(58)
Balance, Ending, Assets	1,199	1,480
Unrealized gains (losses) on Level 3 assets and liabilities held at balance sheet date recognized in net income (loss)		(1)
Corporate and other bonds [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, Beginning, Assets	204	219
Net realized investment gains (losses) and net change in unrealized appreciation (depreciation) included in net income (loss)	1
Net change in unrealized appreciation (depreciation) included in other comprehensive income (loss)	1	2
Purchases	5	110
Sales	(4)	(17)
Settlements	(5)	(20)
Transfers into Level 3	3	26
Transfers out of Level 3	(16)	(18)
Balance, Ending, Assets	189	302
Unrealized gains (losses) on Level 3 assets and liabilities held at balance sheet date recognized in net income (loss)		(1)
States, municipalities and political subdivisions [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, Beginning, Assets	71	96
Net realized investment gains (losses) and net change in unrealized appreciation (depreciation) included in net income (loss)		(3)
Net change in unrealized appreciation (depreciation) included in other comprehensive income (loss)	1
Purchases		85
Sales		(47)
Settlements		(2)
Transfers into Level 3	14
Transfers out of Level 3
Balance, Ending, Assets	86	129
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	331	413
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)	15
Purchases	25	61
Sales
Settlements	(21)	(11)
Transfers into Level 3	21
Transfers out of Level 3	(13)	(16)
Balance, Ending, Assets	359	450
Unrealized gains (losses) on Level 3 assets and liabilities held at balance sheet date recognized in net income (loss)
Commercial Mortgage Backed Securities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, Beginning, Assets	151	129
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)	5
Purchases		73
Sales
Settlements	(1)	(7)
Transfers into Level 3
Transfers out of Level 3	(24)	(24)
Balance, Ending, Assets	126	177
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	446	368
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
Purchases	148	136
Sales	(83)	(99)
Settlements	(72)	(13)
Transfers into Level 3
Transfers out of Level 3	(1)
Balance, Ending, Assets	439	396
Unrealized gains (losses) on Level 3 assets and liabilities held at balance sheet date recognized in net income (loss)
Total asset-backed [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, Beginning, Assets	928	910
Net realized investment gains (losses) and net change in unrealized appreciation (depreciation) included in net income (loss)	3	7
Net change in unrealized appreciation (depreciation) included in other comprehensive income (loss)	14	6
Purchases	173	270
Sales	(83)	(99)
Settlements	(94)	(31)
Transfers into Level 3	21
Transfers out of Level 3	(38)	(40)
Balance, Ending, Assets	924	1,023
Unrealized gains (losses) on Level 3 assets and liabilities held at balance sheet date recognized in net income (loss)
Redeemable preferred stock [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, Beginning, Assets		26
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
Balance, Ending, Assets		26
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	11	34
Net realized investment gains (losses) and net change in unrealized appreciation (depreciation) included in net income (loss)	3	(15)
Net change in unrealized appreciation (depreciation) included in other comprehensive income (loss)	(4)	1
Purchases
Sales	(8)
Settlements
Transfers into Level 3
Transfers out of Level 3		(1)
Balance, Ending, Assets	2	19
Unrealized gains (losses) on Level 3 assets and liabilities held at balance sheet date recognized in net income (loss)		(15)
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
Transfers into Level 3
Transfers out of Level 3
Balance, Ending, Assets		(1)
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		(1)
Settlements
Transfers into Level 3
Transfers out of Level 3
Balance, Ending, Assets		5
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	88	100
Net realized investment gains (losses) and net change in unrealized appreciation (depreciation) included in net income (loss)	10	7
Net change in unrealized appreciation (depreciation) included in other comprehensive income (loss)
Purchases
Sales
Settlements	(11)	(12)
Transfers into Level 3
Transfers out of Level 3
Balance, Ending, Assets	87	95
Unrealized gains (losses) on Level 3 assets and liabilities held at balance sheet date recognized in net income (loss)	1
Separate account business [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, Beginning, Assets	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
Unrealized gains (losses) on Level 3 assets and liabilities held at balance sheet date recognized in net income (loss)