Supplementary Data on Cash Flows (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Cash flows from operating activities:
Net income	$ 119	$ 184	$ (38)	$ 354	$ 281	$ (180)	$ (107)	$ 274	$ 619	$ 268	$ 660
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation									17	4	12
Amortization of deferred policy acquisition costs									715	680	652
Impairment of goodwill											22
Deferred income tax expense (benefit)									118	(105)	342
Realized (gains) losses and impairments on investments									(418)	6	(307)
Equity in earnings of limited partnerships									(131)	(149)	(128)
Net amortization of bond premium									28	26	9
Increase in deferred compensation									2	4	7
Limited partnership distributions									164	166	122
(Increase) decrease in receivables, reinsurance recoverables and reserve credits									(166)	91	(158)
Decrease (increase) in prepaid expenses									63	(56)	10
Increase in deferred policy acquisition costs									(743)	(701)	(667)
(Decrease) increase in accounts payable and accrued expenses									(28)	83	18
Increase in accrued commissions and agent bonuses									20	4	1
Increase (decrease) in loss reserves									99	(85)	(11)
Increase in future life policy benefits and claims reserves									31	28	21
Increase in unearned premiums									187	96	116
Net cash provided by operating activities									$ 577	$ 360	$ 721