Closed Block (Closed Block Revenues and Benefits and Expenses) (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
Revenues
Premiums	$ 646	$ 666	$ 2,060	$ 2,129
Net investment income	710	731	2,177	2,221
Realized investment gains (losses), net	74	243	220	495
Other income	15	(2)	14	30
Total Closed Block revenues	1,445	1,638	4,471	4,875
Benefits and Expenses
Policyholders' benefits	776	827	2,565	2,557
Interest credited to policyholders' account balances	34	35	103	104
Dividends to policyholders'	478	639	1,454	1,848
General and administrative expenses	122	129	372	392
Total Closed Block benefits and expenses	1,410	1,630	4,494	4,901
Closed Block revenues, net of Closed Block benefits and expenses, before income taxes and discontinued operations	35	8	(23)	(26)
Income tax expense (benefit)	29	5	(36)	(32)
Closed Block revenues, net of Closed Block benefits and expenses and income taxes, before discontinued operations	6	3	13	6
Income from discontinued operations, net of taxes	(1)	0	(2)	0
Closed Block revenues, net of Closed Block benefits and expenses, income taxes and discontinued operations	$ 5	$ 3	$ 11	$ 6