Fair Value of Assets and Liabilities (Changes in Level 3 Derivative Assets and Liabilities) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012		Dec. 31, 2011
Equity Contract [Member] | Derivative Financial Instruments, Assets [Member]
Fair Value, beginning of period	$ 83		$ 126
Included In Earnings
Realized investment gains (losses), net	(70)		(29)
Asset management fees and other income	0		0
Purchases	6		0
Sales	0		0
Issuances	0		0
Settlements	0		14
Transfers into Level 3	0	[1]	0	[1]
Transfers out of Level 3	0	[1]	0	[1]
Fair Value, end of period	19		83
Included In Earnings
Realized investment gains (losses), net	(70)		(29)
Asset management fees and other income	0		0
Credit Risk Contract [Member] | Derivative Financial Instruments, Assets [Member]
Fair Value, beginning of period	1
Included In Earnings
Realized investment gains (losses), net	(1)
Asset management fees and other income	0
Purchases	0
Sales	0
Issuances	0
Settlements	0
Transfers into Level 3	0	[1]
Transfers out of Level 3	0	[1]
Transfers out of Level 3	0
Included In Earnings
Realized investment gains (losses), net	(1)
Asset management fees and other income	0
Credit Risk Contract [Member] | Derivative Financial Instruments, Liabilities [Member]
Fair Value, Beginning of period			0
Included In Earnings
Realized investment gains (losses), net			1
Asset management fees and other income			0
Purchases			0
Sales			0
Issuances			0
Settlements			0
Transfers into Level 3			0	[1]
Transfers out of Level 3			0	[1]
Fair Value, End of Period			1
Included In Earnings
Realized investement gains (losses), net			1
Asset management fees and other income			0
Interest Rate Contract [Member] | Derivative Financial Instruments, Liabilities [Member]
Fair Value, Beginning of period	(1)		(12)
Included In Earnings
Realized investment gains (losses), net	4		11
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	[1]	0	[1]
Transfers out of Level 3	0	[1]	0	[1]
Fair Value, End of Period	3		(1)
Included In Earnings
Realized investement gains (losses), net	4		11
Asset management fees and other income	$ 0		$ 0

[1] Transfers into or out of Level 3 are generally reported as the value as of the beginning of the quarter in which the transfer occurs.