Consolidated Statement of Cash Flows (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012		Dec. 31, 2011		Dec. 31, 2010
Cash flows from operating activities
Net income	$ 2,473		$ 1,426		$ 3,216
Adjustments to reconcile net income to net cash provided by operating activities:
Net realized investment gains	(51)	[1]	(55)	[1]	(264)	[1]
Depreciation and amortization	827		802		812
Deferred federal income tax expense	223		63		178
Amortization of deferred acquisition costs	3,910		3,876		3,802
Equity in income from other investments	(342)		(281)		(283)
Change in premiums receivable	(138)		(237)		(29)
Change in reinsurance recoverables	453		809		1,303
Change in deferred acquisition costs	(3,914)		(3,881)		(3,826)
Change in claims and claim adjustment expense reserves	(540)		(154)		(1,971)
Change in unearned premium reserves	123		188		63
Other operating activities	206		(387)		53
Net cash provided by operating activities	3,230		2,169		3,054
Cash flows from investing activities
Proceeds from maturities of fixed maturities	8,369		7,404		5,896
Proceeds from sales of investments, fixed maturities	1,087		1,161		3,713
Proceeds from sales of investments, equity securities	37		135		201
Proceeds from sales of investments, real estate investments	53		1		10
Proceeds from sales of investments, other investments	835		594		717
Purchases of investments, fixed maturities	(10,447)		(8,704)		(6,785)
Purchases of investments, equity securities	(48)		(131)		(61)
Purchases of investments, real estate investments	(95)		(66)		(21)
Purchases of investments, other investments	(534)		(889)		(514)
Net sales (purchases) of short-term securities	117		2,018		(699)
Securities transactions in course of settlement	(23)				(30)
Other investing activities	(323)		(371)		(318)
Net cash provided by (used in) investing activities	(972)		1,152		2,109
Cash flows from financing activities
Payment of debt	(258)		(8)		(1,160)
Issuance of debt					1,234
Dividends paid to shareholders	(694)		(665)		(673)
Issuance of common stock - employee share options	295		314		408
Treasury stock acquired - share repurchase authorization	(1,474)		(2,919)		(4,998)
Treasury stock acquired - net employee share-based compensation	(53)		(46)		(40)
Excess tax benefits from share-based payment arrangements	38		18		8
Net cash used in financing activities	(2,146)		(3,306)		(5,221)
Effect of exchange rate changes on cash	4		(1)		3
Net increase (decrease) in cash	116		14		(55)
Cash at beginning of year	214		200		255
Cash at end of year	330		214		200
Supplemental disclosure of cash flow information
Income taxes paid	188		218		784
Interest paid	$ 375		$ 382		$ 397

[1] Total other-than-temporary impairment (OTTI) gains were $27 million, $30 million and $7 million for the years ended December 31, 2012, 2011 and 2010, respectively. Of total OTTI, credit losses of $(15) million, $(25) million and $(26) million for the years ended December 31, 2012, 2011 and 2010, respectively, were recognized in net realized investment gains. In addition, unrealized gains from other changes in total OTTI of $42 million, $55 million and $33 million for the years ended December 31, 2012, 2011 and 2010, respectively, were recognized in other comprehensive income as part of changes in net unrealized gains on investment securities having credit losses recognized in the consolidated statement of income.