Fair Value Measurements - Changes in Level 3 Assets and Liabilities (Details) (General Accounts [Member], USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2013		Mar. 31, 2012
GMIB Liabilities [Member]
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Balance at January 1,	$ (1,170)		$ (1,333)
Gains (losses) included in shareholders' net income:
GMIB fair value gain/(loss)	49		153
Other	0		0
Total gains (losses) included in shareholders' net income	49		153
Gains (losses) included in other comprehensive income	0		0
Gains (losses) required to adjust future policy benefits for settlement annuities	0	[1]	0	[1]
Purchases, issuances, settlements:
Purchases	0		0
Sales	0		0
Settlements	22		18
Total purchases, sales, and settlements	22		18
Transfers into/(out of) Level 3:
Transfer into Level 3	0		0
Transfers out of Level 3	0		0
Transfers into/(out of) Level 3	0		0
Balance at March 31,	(1,099)		(1,162)
Total gains (losses) included in income attributable to instruments held at the reporting date	49		153
GMIB Net [Member]
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Balance at January 1,	(548)		(621)
Gains (losses) included in shareholders' net income:
GMIB fair value gain/(loss)	0		67
Other	1		0
Total gains (losses) included in shareholders' net income	1		67
Gains (losses) included in other comprehensive income	0		0
Gains (losses) required to adjust future policy benefits for settlement annuities	0	[1]	0	[1]
Purchases, issuances, settlements:
Purchases	0		0
Sales	0		0
Settlements	565		9
Total purchases, sales, and settlements	565		9
Transfers into/(out of) Level 3:
Transfer into Level 3	0		0
Transfers out of Level 3	0		0
Transfers into/(out of) Level 3	0		0
Balance at March 31,	18		(545)
Total gains (losses) included in income attributable to instruments held at the reporting date	1		67
Fixed Maturities And Equity Securities [Member]
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Balance at January 1,	1,351		1,002
Gains (losses) included in shareholders' net income:
GMIB fair value gain/(loss)	0		0
Other	6		0
Total gains (losses) included in shareholders' net income	6		0
Gains (losses) included in other comprehensive income	(1)		8
Gains (losses) required to adjust future policy benefits for settlement annuities	(5)	[1]	(11)	[1]
Purchases, issuances, settlements:
Purchases	5		37
Sales	(12)		0
Settlements	(51)		(3)
Total purchases, sales, settlements	(58)		34
Transfers into/(out of) Level 3:
Transfers into Level 3	54		73
Transfers out of Level 3	(59)		(34)
Total transfers into/(out of) Level 3	(5)		39
Balance at March 31,	1,288		1,072
Total gains (losses) included in income attributable to instruments held at the reporting date	2		0
GMIB Assets [Member]
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Balance at January 1,	622		712
Gains (losses) included in shareholders' net income:
GMIB fair value gain/(loss)	(49)		(86)
Other	1		0
Total gains (losses) included in shareholders' net income	(48)		(86)
Gains (losses) included in other comprehensive income	0		0
Gains (losses) required to adjust future policy benefits for settlement annuities	0	[1]	0	[1]
Purchases, issuances, settlements:
Purchases	0		0
Sales	0		0
Settlements	543		(9)
Total purchases, sales, settlements	543		(9)
Transfers into/(out of) Level 3:
Transfers into Level 3	0		0
Transfers out of Level 3	0		0
Total transfers into/(out of) Level 3	0		0
Balance at March 31,	1,117		617
Total gains (losses) included in income attributable to instruments held at the reporting date	$ (48)		$ (86)

[1] Amounts do not accrue to shareholders.