Income Taxes (tables)

12 Months Ended

Dec. 31, 2012

Income Taxes disclosure

Composition of income tax expense (benefit) included in consolidated statement of income and common shareholders' equity [Table Text Block]

(for the year ended December 31, in millions)	2012		2011			2010
Composition of income tax expense (benefit) included in the consolidated statement of income
Current expense (benefit):
Federal	$	406	$	(176	)	$	846
Foreign		45		34			78
State		3		3			10
Total current tax expense (benefit)		454		(139	)		934
Deferred expense (benefit):
Federal		223		63			178
Foreign		16		2			(22	)
Total deferred tax expense		239		65			156
Total income tax expense (benefit) included in the consolidated statement of income		693		(74	)		1,090
Composition of income tax included in common shareholders' equity
Expense (benefit) relating to stock-based compensation, and the expense (benefit) related to the changes in unrealized appreciation on investments, unrealized loss on foreign exchange, unrealized loss on derivatives and other comprehensive income		57		399			(2	)
Total income tax expense included in the consolidated financial statements	$	750	$	325		$	1,088

Effective tax rate [Table Text Block]

(for the year ended December 31, in millions)	2012			2011			2010
Effective tax rate
Income before federal, foreign and state income taxes	$	3,166		$	1,352		$	4,306
Statutory tax rate		35	%		35	%		35	%
Expected federal income tax expense		1,108			473			1,507
Tax effect of:
Nontaxable investment income		(427	)		(449	)		(476	)
Favorable resolution of prior year tax matters		—			(104	)		—
Other, net		12			6			59
Total income tax expense (benefit)	$	693		$	(74	)	$	1,090
Effective tax rate		22	%		(5	)%		25	%

Deferred tax assets and liabilities [Table Text Block]

(at December 31, in millions)	2012			2011
Deferred tax assets
Claims and claim adjustment expense reserves	$	888		$	936
Unearned premium reserves		689			680
Other		741			844
Total gross deferred tax assets		2,318			2,460
Deferred tax liabilities
Deferred acquisition costs		590			585
Investments		1,800			1,650
Internally developed software		134			128
Other		132			90
Total gross deferred tax liabilities		2,656			2,453
Total deferred tax asset (liability)	$	(338	)	$	7

Reconciliation of unrecognized tax benefits [Table Text Block]

(in millions)	2012			2011
Balance at January 1	$	37		$	103
Additions for tax positions of prior years		2			1
Reductions for tax positions of prior years		(15	)		(68	)
Additions based on tax positions related to current year		—			1
Balance at December 31	$	24		$	37