Consolidated Statements of Shareholders' Equity (USD $) In Millions	Total	Preferred Stock [Member]	Common Stock [Member]	Paid-In Surplus [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Unrealized Appreciation (Depreciation) of Investments Including Unrealized Other-Than-Temporary Impairment Losses [Member]	Foreign Currency Translation Gains (Losses) [Member]	Postretirement Benefit Costs Not Yet Recognized in Net Income [Member]	Treasury Stock [Member]
Balance, End of Year at Dec. 31, 2008		$ 0	$ 372	$ 253	$ 14,509		$ (143)	$ (10)	$ (582)	$ (967)
Cumulative Effect, as of April 1, 2009, of Change in Accounting Principle, Net of Tax					30		(30)
Net Income	2,183				2,183
Dividends Declared (per share $1.56, $1.48 and $1.40)					(487)
Repurchase of Shares										(1,065)
Changes Related to Stock-Based Employee Compensation (includes tax benefit of $24, $15 and $6)				(29)
Change During Year, Net of Tax	1,485						1,217	170	98
Shares Issued Under Stock-Based Employee Compensation Plans										115
Balance, End of Year at Dec. 31, 2009	15,634	0	372	224	16,235	720	1,044	160	(484)	(1,917)
Cumulative Effect, as of April 1, 2009, of Change in Accounting Principle, Net of Tax					0		0
Net Income	2,174				2,174
Dividends Declared (per share $1.56, $1.48 and $1.40)					(466)
Repurchase of Shares										(2,008)
Changes Related to Stock-Based Employee Compensation (includes tax benefit of $24, $15 and $6)				(16)
Change During Year, Net of Tax	70						76	(18)	12
Shares Issued Under Stock-Based Employee Compensation Plans										142
Balance, End of Year at Dec. 31, 2010	15,530	0	372	208	17,943	790	1,120	142	(472)	(3,783)
Cumulative Effect, as of April 1, 2009, of Change in Accounting Principle, Net of Tax					0		0
Net Income	1,678				1,678
Dividends Declared (per share $1.56, $1.48 and $1.40)					(445)
Repurchase of Shares										(1,718)
Changes Related to Stock-Based Employee Compensation (includes tax benefit of $24, $15 and $6)				(18)
Change During Year, Net of Tax	405						616	4	(215)
Shares Issued Under Stock-Based Employee Compensation Plans										142
Balance, End of Year at Dec. 31, 2011	$ 15,574	$ 0	$ 372	$ 190	$ 19,176	$ 1,195	$ 1,736	$ 146	$ (687)	$ (5,359)