Shareholders' Equity (Details) (USD $)	12 Months Ended				1 Months Ended		12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009	Dec. 31, 2008	Jun. 30, 2011 Open Market Share Repurchases	May 31, 2010 Open Market Share Repurchases	Dec. 31, 2011 Open Market Share Repurchases	Dec. 31, 2010 Open Market Share Repurchases	Dec. 31, 2011 Franchise Advisor Deferral Plan	Dec. 31, 2010 Franchise Advisor Deferral Plan
Components of accumulated other comprehensive income (loss), net of tax
Net unrealized securities gains	$ 770,000,000	$ 615,000,000
Net unrealized derivatives gains	(11,000,000)	18,000,000	3,000,000	(8,000,000)
Defined benefit plans	(75,000,000)	(24,000,000)	(20,000,000)	(39,000,000)
Foreign currency translation	(46,000,000)	(44,000,000)
Total	638,000,000	565,000,000
Common Share Repurchases:
Maximum amount authorized for repurchase of common stock					2,000,000,000	1,500,000,000
Repurchase of common shares (in shares)							27,900,000	13,100,000	300,000	100,000
Repurchase of common shares							1,500,000,000	573,000,000	13,000,000	7,000,000
Remaining Balance under Stock Repurchase Program							1,500,000,000
Restricted shares forfeited, recorded as treasury shares	100,000	300,000	300,000
Number of shares reacquired through surrender of restricted shares	500,000	400,000	500,000
Value of shares reacquired through surrender of restricted shares	25,000,000	17,000,000	11,000,000
Treasury shares reissued for restricted stock award grants (in shares)	1,700,000
Treasury shares reissued for restricted stock award grants and Franchise Advisor Deferral Plan (in shares)	1,700,000
Common stock issued and sold (in shares)			36,000,000
Proceeds from shares issued used for general corporate purposes			$ 869,000,000