Fair Value (Unobservable Input Reconciliation) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
U.S. corporate securities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, Beginning of Period	$ 1,267	$ 1,493	$ 1,434	$ 1,432
Earnings [Abstract]
Net Investment Income	3	2	5	3
Net Investment Gains (Losses)	(3)	0	(3)	0
Net Derivative Gains (Losses)	0	0	0	0
Other Comprehensive Income (Loss)	(40)	14	(13)	(2)
Purchases	111	30	139	122
Sales	(75)	(31)	(126)	(55)
Issuances	0	0	0	0
Settlements	0	0	0	0
Transfers Into Level 3	8	17	56	27
Transfers Out of Level 3	(102)	(3)	(323)	(5)
Balance, End of Period	1,169	1,522	1,169	1,522
Changes in unrealized gains (losses) relating to assets still held at end of period included in earnings [Abstract]
Net Investment Income	3	2	5	4
Net Investment Gains (Losses)	0	0	0	0
Net Derivative Gains (Losses)	0	0	0	0
Foreign corporate securities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, Beginning of Period	786	622	868	580
Earnings [Abstract]
Net Investment Income	0	0	0	0
Net Investment Gains (Losses)	(1)	(6)	(3)	(8)
Net Derivative Gains (Losses)	0	0	0	0
Other Comprehensive Income (Loss)	(29)	19	(23)	20
Purchases	69	77	87	80
Sales	(25)	(11)	(65)	(16)
Issuances	0	0	0	0
Settlements	0	0	0	0
Transfers Into Level 3	23	37	22	53
Transfers Out of Level 3	(10)	(40)	(73)	(11)
Balance, End of Period	813	698	813	698
Changes in unrealized gains (losses) relating to assets still held at end of period included in earnings [Abstract]
Net Investment Income	0	0	0	0
Net Investment Gains (Losses)	0	(6)	0	(6)
Net Derivative Gains (Losses)	0	0	0	0
RMBS [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, Beginning of Period	314	356	278	239
Earnings [Abstract]
Net Investment Income	0	0	0	0
Net Investment Gains (Losses)	0	(3)	0	(2)
Net Derivative Gains (Losses)	0	0	0	0
Other Comprehensive Income (Loss)	0	9	8	16
Purchases	86	1	85	0
Sales	(51)	(99)	(27)	(20)
Issuances	0	0	0	0
Settlements	0	0	0	0
Transfers Into Level 3	3	0	12	0
Transfers Out of Level 3	0	(31)	(4)	0
Balance, End of Period	352	233	352	233
Changes in unrealized gains (losses) relating to assets still held at end of period included in earnings [Abstract]
Net Investment Income	0	0	0	0
Net Investment Gains (Losses)	0	(2)	0	(2)
Net Derivative Gains (Losses)	0	0	0	0
ABS [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, Beginning of Period	420	257	343	220
Earnings [Abstract]
Net Investment Income	0	0	1	0
Net Investment Gains (Losses)	0	0	0	0
Net Derivative Gains (Losses)	0	0	0	0
Other Comprehensive Income (Loss)	(1)	0	(1)	1
Purchases	61	52	124	95
Sales	(42)	(1)	(16)	(9)
Issuances	0	0	0	0
Settlements	0	0	0	0
Transfers Into Level 3	0	0	0	0
Transfers Out of Level 3	(15)	(19)	(28)	(18)
Balance, End of Period	423	289	423	289
Changes in unrealized gains (losses) relating to assets still held at end of period included in earnings [Abstract]
Net Investment Income	0	0	1	0
Net Investment Gains (Losses)	0	0	0	0
Net Derivative Gains (Losses)	0	0	0	0
State and political subdivision securities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, Beginning of Period	25	25	25	23
Earnings [Abstract]
Net Investment Income	0	0	0	0
Net Investment Gains (Losses)	0	0	0	0
Net Derivative Gains (Losses)	0	0	0	0
Other Comprehensive Income (Loss)	0	0	0	2
Purchases	0	0	0	0
Sales	0	0	0	0
Issuances	0	0	0	0
Settlements	0	0	0	0
Transfers Into Level 3	0	0	0	0
Transfers Out of Level 3	(19)	0	(19)	0
Balance, End of Period	6	25	6	25
Changes in unrealized gains (losses) relating to assets still held at end of period included in earnings [Abstract]
Net Investment Income	0	0	0	0
Net Investment Gains (Losses)	0	0	0	0
Net Derivative Gains (Losses)	0	0	0	0
CMBS [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, Beginning of Period	106	152	125	147
Earnings [Abstract]
Net Investment Income	0	0	0	0
Net Investment Gains (Losses)	1	(1)	0	(2)
Net Derivative Gains (Losses)	0	0	0	0
Other Comprehensive Income (Loss)	0	1	2	6
Purchases	4	20	6	21
Sales	(40)	(19)	(53)	(29)
Issuances	0	0	0	0
Settlements	0	0	0	0
Transfers Into Level 3	0	15	0	15
Transfers Out of Level 3	(5)	(10)	(14)	0
Balance, End of Period	66	158	66	158
Changes in unrealized gains (losses) relating to assets still held at end of period included in earnings [Abstract]
Net Investment Income	0	0	0	0
Net Investment Gains (Losses)	0	0	0	0
Net Derivative Gains (Losses)	0	0	0	0
Foreign government debt securities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, Beginning of Period	2	2	3	2
Earnings [Abstract]
Net Investment Income	0	0	0	0
Net Investment Gains (Losses)	0	0	0	0
Net Derivative Gains (Losses)	0	0	0	0
Other Comprehensive Income (Loss)	0	0	(1)	0
Purchases	0	0	0	0
Sales	0	0	0	0
Issuances	0	0	0	0
Settlements	0	0	0	0
Transfers Into Level 3	0	0	0	0
Transfers Out of Level 3	0	0	0	0
Balance, End of Period	2	2	2	2
Changes in unrealized gains (losses) relating to assets still held at end of period included in earnings [Abstract]
Net Investment Income	0	0	0	0
Net Investment Gains (Losses)	0	0	0	0
Net Derivative Gains (Losses)	0	0	0	0
Non-redeemable preferred stock [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, Beginning of Period	79	92	93	76
Earnings [Abstract]
Net Investment Income	0	0	0	0
Net Investment Gains (Losses)	0	0	(1)	0
Net Derivative Gains (Losses)	0	0	0	0
Other Comprehensive Income (Loss)	2	(1)	6	15
Purchases	0	0	1	0
Sales	0	0	(18)	0
Issuances	0	0	0	0
Settlements	0	0	0	0
Transfers Into Level 3	0	0	0	0
Transfers Out of Level 3	0	0	0	0
Balance, End of Period	81	91	81	91
Changes in unrealized gains (losses) relating to assets still held at end of period included in earnings [Abstract]
Net Investment Income	0	0	0	0
Net Investment Gains (Losses)	0	0	(2)	0
Net Derivative Gains (Losses)	0	0	0	0
Common Stock [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, Beginning of Period	26	25	26	21
Earnings [Abstract]
Net Investment Income	0	0	0	0
Net Investment Gains (Losses)	0	0	0	(3)
Net Derivative Gains (Losses)	0	0	0	0
Other Comprehensive Income (Loss)	1	(1)	2	4
Purchases	3	0	2	0
Sales	0	(2)	0	0
Issuances	0	0	0	0
Settlements	0	0	0	0
Transfers Into Level 3	0	0	0	0
Transfers Out of Level 3	0	0	0	0
Balance, End of Period	30	22	30	22
Changes in unrealized gains (losses) relating to assets still held at end of period included in earnings [Abstract]
Net Investment Income	0	0	0	0
Net Investment Gains (Losses)	0	0	0	(3)
Net Derivative Gains (Losses)	0	0	0	0
Short-term Investments [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, Beginning of Period	396	20	13	10
Earnings [Abstract]
Net Investment Income	0	0	0	0
Net Investment Gains (Losses)	0	0	0	0
Net Derivative Gains (Losses)	0	0	0	0
Other Comprehensive Income (Loss)	0	0	0	0
Purchases	2	22	2	22
Sales	(366)	(20)	(13)	(10)
Issuances	0	0	0	0
Settlements	0	0	0	0
Transfers Into Level 3	0	0	0	0
Transfers Out of Level 3	(30)	0	0	0
Balance, End of Period	2	22	2	22
Changes in unrealized gains (losses) relating to assets still held at end of period included in earnings [Abstract]
Net Investment Income	0	0	0	0
Net Investment Gains (Losses)	0	0	0	0
Net Derivative Gains (Losses)	0	0	0	0
Interest rate contracts [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, Beginning of Period	106	95	119	174
Earnings [Abstract]
Net Investment Income	0	0	0	0
Net Investment Gains (Losses)	0	0	0	0
Net Derivative Gains (Losses)	(26)	22	(21)	10
Other Comprehensive Income (Loss)	(20)	71	(35)	14
Purchases	0	0	0	0
Sales	0	0	0	0
Issuances	0	0	0	0
Settlements	(12)	(19)	(15)	(29)
Transfers Into Level 3	0	0	0	0
Transfers Out of Level 3	(1)	0	(1)	0
Balance, End of Period	47	169	47	169
Changes in unrealized gains (losses) relating to assets still held at end of period included in earnings [Abstract]
Net Investment Income	0	0	0	0
Net Investment Gains (Losses)	0	0	0	0
Net Derivative Gains (Losses)	(22)	19	(18)	7
Foreign currency contracts [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, Beginning of Period	0	0	0	0
Earnings [Abstract]
Net Investment Income	0	0	0	0
Net Investment Gains (Losses)	0	0	0	0
Net Derivative Gains (Losses)	0	0	0	0
Other Comprehensive Income (Loss)	0	0	0	0
Purchases	0	0	0	0
Sales	0	0	0	0
Issuances	0	0	0	0
Settlements	0	0	0	0
Transfers Into Level 3	0	0	0	0
Transfers Out of Level 3	0	0	0	0
Balance, End of Period	0	0	0	0
Changes in unrealized gains (losses) relating to assets still held at end of period included in earnings [Abstract]
Net Investment Income	0	0	0	0
Net Investment Gains (Losses)	0	0	0	0
Net Derivative Gains (Losses)	0	0	0	0
Credit contracts [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, Beginning of Period	8	9	10	(1)
Earnings [Abstract]
Net Investment Income	0	0	0	0
Net Investment Gains (Losses)	0	0	0	0
Net Derivative Gains (Losses)	(2)	(3)	(4)	7
Other Comprehensive Income (Loss)	0	0	0	0
Purchases	0	0	0	0
Sales	0	0	0	0
Issuances	0	0	0	0
Settlements	0	0	0	0
Transfers Into Level 3	0	0	0	0
Transfers Out of Level 3	0	0	0	0
Balance, End of Period	6	6	6	6
Changes in unrealized gains (losses) relating to assets still held at end of period included in earnings [Abstract]
Net Investment Income	0	0	0	0
Net Investment Gains (Losses)	0	0	0	0
Net Derivative Gains (Losses)	(2)	(3)	(4)	7
Equity market contracts [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, Beginning of Period	(86)	(17)	(51)	43
Earnings [Abstract]
Net Investment Income	0	0	0	0
Net Investment Gains (Losses)	0	0	0	0
Net Derivative Gains (Losses)	2	11	(25)	(49)
Other Comprehensive Income (Loss)	0	0	0	0
Purchases	0	0	0	0
Sales	0	0	0	0
Issuances	0	0	0	0
Settlements	0	0	(8)	0
Transfers Into Level 3	0	0	0	0
Transfers Out of Level 3	0	0	0	0
Balance, End of Period	(84)	(6)	(84)	(6)
Changes in unrealized gains (losses) relating to assets still held at end of period included in earnings [Abstract]
Net Investment Income	0	0	0	0
Net Investment Gains (Losses)	0	0	0	0
Net Derivative Gains (Losses)	3	11	(25)	(49)
Net Embedded Derivatives [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, Beginning of Period	2,550	1,148	2,290	1,032
Earnings [Abstract]
Net Investment Income	0	0	0	0
Net Investment Gains (Losses)	0	0	0	0
Net Derivative Gains (Losses)	(81)	69	173	181
Other Comprehensive Income (Loss)	0	0	0	0
Purchases	0	0	0	0
Sales	0	0	0	0
Issuances	0	0	0	0
Settlements	(16)	(3)	(10)	1
Transfers Into Level 3	0	0	0	0
Transfers Out of Level 3	0	0	0	0
Balance, End of Period	2,453	1,214	2,453	1,214
Changes in unrealized gains (losses) relating to assets still held at end of period included in earnings [Abstract]
Net Investment Income	0	0	0	0
Net Investment Gains (Losses)	0	0	0	0
Net Derivative Gains (Losses)	(74)	72	186	186
Separate account assets [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, Beginning of Period	139	149	141	130
Earnings [Abstract]
Net Investment Income	0	0	0	0
Net Investment Gains (Losses)	0	0	0	19
Net Derivative Gains (Losses)	0	0	0	0
Other Comprehensive Income (Loss)	0	0	0	0
Purchases	2	1	2	2
Sales	(2)	(1)	(3)	(2)
Issuances	0	0	0	0
Settlements	0	0	0	0
Transfers Into Level 3	1	0	0	0
Transfers Out of Level 3	0	0	0	0
Balance, End of Period	140	149	140	149
Changes in unrealized gains (losses) relating to assets still held at end of period included in earnings [Abstract]
Net Investment Income	0	0	0	0
Net Investment Gains (Losses)	0	0	0	0
Net Derivative Gains (Losses)	$ 0	$ 0	$ 0	$ 0