Fair Value Measurements - Changes in Level 3 Assets and Liabilities (Details) (General Accounts [Member], USD $) In Millions, unless otherwise specified	3 Months Ended				6 Months Ended
	Jun. 30, 2013		Jun. 30, 2012		Jun. 30, 2013		Jun. 30, 2012
GMIB Liabilities [Member]
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning Balance	$ (1,099)		$ (1,162)		$ (1,170)		$ (1,333)
Gains (losses) included in shareholders' net income:
GMIB fair value gain/(loss)	156		(186)		205		(33)
Other	0		0		0		0
Total gains (losses) included in shareholders' net income	156		(186)		205		(33)
Gains (losses) included in other comprehensive income	0		0		0		0
Gains (losses) required to adjust future policy benefits for settlement annuities	0	[1]	0	[1]	0	[1]	0	[1]
Purchases, issuances, settlements:
Purchases	0		0		0		0
Sales	0				0
Settlements	21		16		43		34
Total purchases, sales, and settlements	21		16		43		34
Transfers into/(out of) Level 3:
Transfer into Level 3	0		0		0		0
Transfers out of Level 3	0		0		0		0
Transfers into/(out of) Level 3	0		0		0		0
Ending Balance	(922)		(1,332)		(922)		(1,332)
Total gains (losses) included in income attributable to instruments held at the reporting date	156		(186)		205		(33)
GMIB Net [Member]
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning Balance	18		(545)		(548)		(621)
Gains (losses) included in shareholders' net income:
GMIB fair value gain/(loss)	0		(87)		0		(20)
Other	1		0		2		0
Total gains (losses) included in shareholders' net income	1		(87)		2		(20)
Gains (losses) included in other comprehensive income	0		0		0		0
Gains (losses) required to adjust future policy benefits for settlement annuities	0	[1]	0	[1]	0	[1]	0	[1]
Purchases, issuances, settlements:
Purchases	0		0		0		0
Sales	0				0
Settlements	4		7		569		16
Total purchases, sales, and settlements	4		7		569		16
Transfers into/(out of) Level 3:
Transfer into Level 3	0		0		0		0
Transfers out of Level 3	0		0		0		0
Transfers into/(out of) Level 3	0		0		0		0
Ending Balance	23		(625)		23		(625)
Total gains (losses) included in income attributable to instruments held at the reporting date	1		(87)		2		(20)
Fixed Maturities And Equity Securities [Member]
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Beginning Balance	1,288		1,072		1,351		1,002
Gains (losses) included in shareholders' net income:
GMIB fair value gain/(loss)	0		0		0		0
Other	4		3		10		3
Total gains (losses) included in shareholders' net income	4		3		10		3
Gains (losses) included in other comprehensive income	(16)		(3)		(17)		5
Gains (losses) required to adjust future policy benefits for settlement annuities	(33)	[1]	7	[1]	(38)	[1]	(4)	[1]
Purchases, issuances, settlements:
Purchases	35		30		40		67
Sales	(18)				(30)
Settlements	(10)		(26)		(61)		(29)
Total purchases, sales, settlements	7		4		(51)		38
Transfers into/(out of) Level 3:
Transfers into Level 3	15		46		69		119
Transfers out of Level 3	(56)		(1)		(115)		(35)
Total transfers into/(out of) Level 3	(41)		45		(46)		84
Ending Balance	1,209		1,128		1,209		1,128
Total gains (losses) included in income attributable to instruments held at the reporting date	2		0		4		0
GMIB Assets [Member]
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Beginning Balance	1,117		617		622		712
Gains (losses) included in shareholders' net income:
GMIB fair value gain/(loss)	(156)		99		(205)		13
Other	1		0		2		0
Total gains (losses) included in shareholders' net income	(155)		99		(203)		13
Gains (losses) included in other comprehensive income	0		0		0		0
Gains (losses) required to adjust future policy benefits for settlement annuities	0	[1]	0	[1]	0	[1]	0	[1]
Purchases, issuances, settlements:
Purchases	0		0		0		0
Sales	0				0
Settlements	(17)		(9)		526		(18)
Total purchases, sales, settlements	(17)		(9)		526		(18)
Transfers into/(out of) Level 3:
Transfers into Level 3	0		0		0		0
Transfers out of Level 3	0		0		0		0
Total transfers into/(out of) Level 3	0		0		0		0
Ending Balance	945		707		945		707
Total gains (losses) included in income attributable to instruments held at the reporting date	$ (155)		$ 99		$ (203)		$ 13

[1] Amounts do not accrue to shareholders.