Fair Value of Assets and Liabilities (Changes in Level 3 Derivative Assets and Liabilities) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011	Jun. 30, 2011
Equity Contract [Member] | Derivative Financial Instruments, Assets [Member]
Fair Value, beginning of period	$ 40		$ 83	$ 127	$ 82
Included In Earnings
Realized investment gains (losses), net	(15)	75	(63)	34
Asset management fees and other income	0	0	0	0
Purchases	1	0	6	0
Sales	0	0	0	0
Issuances	0	0	0	0
Settlements	0	(7)	0	(11)
Transfers into Level 3	0	0	0	0
Transfers out of Level 3	0	0	0	0
Fair Value, end of period	26	150	26	150	82
Included In Earnings
Realized investment gains (losses), net	(15)	75	(63)	34
Asset management fees and other income	0	0	0	0
Credit Risk Contract [Member] | Derivative Financial Instruments, Assets [Member]
Fair Value, beginning of period	0		1	0	2
Included In Earnings
Realized investment gains (losses), net	0	1	(1)	3
Asset management fees and other income	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
Fair Value, end of period	0	3	0	3	2
Included In Earnings
Realized investment gains (losses), net	0	1	(1)	3
Asset management fees and other income	0	0	0
Interest Rate Contract [Member] | Derivative Financial Instruments, Assets [Member]
Fair Value, beginning of period	2		(1)
Included In Earnings
Realized investment gains (losses), net	5		8
Asset management fees and other income	0		0
Purchases	0		0
Sales	0		0
Issuances	0		0
Settlements	0		0
Transfers into Level 3	0		0
Transfers out of Level 3	0		0
Fair Value, end of period	7		7
Included In Earnings
Realized investment gains (losses), net	5		8
Asset management fees and other income	0		0
Interest Rate Contract [Member] | Derivative Financial Instruments, Liabilities [Member]
Fair Value, Beginning of period				(12)	(7)
Included In Earnings
Realized investment gains (losses), net		0		5
Asset management fees and other income		0		0
Purchases		0		0
Sales		0		0
Issuances		0		0
Settlements		0		0
Transfers into Level 3		0		0
Transfers out of Level 3		0		0
Fair Value, End of Period		(7)		(7)	(7)
Included In Earnings
Realized investement gains (losses), net		0		5
Asset management fees and other income		$ 0		$ 0