Consolidated Statements Of Shareholders' Equity (USD $) In Millions	Total	Common Shares	Common Shares in Treasury	Additional Paid-in Capital	Retained Earnings	Deferred Compensation Obligation	Accumulated Other Comprehensive Income	Net unrealized appreciation on investments	Cumulative Translation Adjustment	Accumulated Defined Benefit Plans Adjustment [Member]	Common Shares Issued To Employee Trust
Balance – beginning of year at Dec. 31, 2010		$ 10,161	$ (330)	$ 5,623	$ 5,787	$ 2		$ 1,399	$ 262	$ (67)	$ (2)
Net shares redeemed under employee share-based compensation plans				(104)
Exercise of stock options		47		16
Dividends declared on Common Shares-par value reduction		(113)
Common Shares repurchased			(132)
Common Shares issued in treasury, net of net shares redeemed under employee share-based compensation plans			135
Share-based compensation expense and other				139
Tax benefit on share-based compensation expense				6
Net income	1,540				1,540
Net income at Jan. 01, 2011 (Scenario, Previously Reported)	1,540
Funding of dividends declared from Additional paid-in capital				354	(354)
Dividends declared on Common Shares					(354)
Decrease to obligation						(2)
Change in year, net of income tax benefit (expense) of $408, $(198), and $(157)								316
Change in year, net of income tax benefit (expense) of $63, $(35) and $1									(4)
Movement In Common Shares Issued To Employee Trust											2
Balance - end of year at Dec. 31, 2011	24,332	10,095	(327)	5,326	7,327	0	1,911	1,715	258	(62)	0
Net shares redeemed under employee share-based compensation plans				(93)
Exercise of stock options		0		(7)
Dividends declared on Common Shares-par value reduction		(504)
Common Shares repurchased			(7)
Common Shares issued in treasury, net of net shares redeemed under employee share-based compensation plans			175
Share-based compensation expense and other				135
Tax benefit on share-based compensation expense				18
Net income	2,706				2,706
Net income at Jan. 01, 2012 (Scenario, Previously Reported)	2,706
Funding of dividends declared from Additional paid-in capital				(200)	200
Dividends declared on Common Shares					(200)
Decrease to obligation						0
Change in year, net of income tax benefit (expense) of $408, $(198), and $(157)								918
Change in year, net of income tax benefit (expense) of $63, $(35) and $1									81
Movement In Common Shares Issued To Employee Trust											0
Balance - end of year at Dec. 31, 2012 (Scenario, Previously Reported)	27,531
Balance - end of year at Dec. 31, 2012	27,531	9,591	(159)	5,179	10,033	0	2,887	2,633	339	(85)	0
Net shares redeemed under employee share-based compensation plans				(126)
Exercise of stock options		0		(42)
Dividends declared on Common Shares-par value reduction		(692)
Common Shares repurchased			(290)
Common Shares issued in treasury, net of net shares redeemed under employee share-based compensation plans			194
Share-based compensation expense and other				191
Tax benefit on share-based compensation expense				36
Net income	3,758				3,758
Funding of dividends declared from Additional paid-in capital				0
Dividends declared on Common Shares
Decrease to obligation						0
Change in year, before reclassification from AOCI, net of income tax benefit of $391								(1,371)
Amounts reclassified from AOCI, net of income tax benefit of $17								(88)
Change in year, net of income tax benefit (expense) of $408, $(198), and $(157)								(1,459)	(276)
Change in year, net of income tax benefit (expense) of $63, $(35) and $1										0
Movement In Common Shares Issued To Employee Trust											0
Balance - end of year at Dec. 31, 2013	$ 28,825	$ 8,899	$ (255)	$ 5,238	$ 13,791	$ 0	$ 1,152	$ 1,174	$ 63	$ (85)	$ 0