Shareholders' Equity (Details) (USD $)	3 Months Ended								12 Months Ended
	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2000	Oct. 31, 2013
Treasury Stock, Value, Acquired, Cost Method									$ 800,000,000	$ 1,600,000,000	$ 819,200,000
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest	15,388,100,000				17,640,700,000				15,388,100,000	17,640,700,000
Common stock shares in treasury, shares in thousands	810,000				833,000				810,000	833,000
Net income	428,500,000	500,600,000	733,500,000	727,900,000	727,500,000	1,203,100,000	1,206,200,000	1,548,000,000	2,390,500,000	4,684,800,000	4,088,600,000
Treasury Stock, Retired, Cost Method, Amount									0	0	(100,000)
Preferred Stock, Shares Authorized	5,000,000								5,000,000
Preferred Stock, Shares Issued	0				0				0	0
Common Stock, Shares Held in Employee Trust, Shares	50,000,000				50,000,000				50,000,000	50,000,000
Employee benefit trust	3,013,200,000				3,013,200,000				3,013,200,000	3,013,200,000
Other comprehensive income (loss)									(1,989,100,000)	1,794,400,000	61,500,000
Allocated Share-based Compensation Expense									156,000,000	144,900,000	141,500,000
Issued shares, shares in thousands	1,111,437,000				1,117,628,000				1,111,437,000	1,117,628,000
Additional Paid-in Capital [Member]
Treasury Stock, Retired, Cost Method, Amount
Retained Earnings [Member]
Net income									2,390,500,000	4,684,800,000	4,088,600,000
Treasury Stock, Retired, Cost Method, Amount									(792,100,000)	(1,677,800,000)	(711,700,000)
Treasury Stock [Member]
Treasury Stock, Value, Acquired, Cost Method									800,000,000	1,600,000,000	819,200,000
Treasury Stock, Retired, Cost Method, Amount									(800,000,000)	(1,698,100,000)	(721,100,000)
Treasury Stock, Shares, Retired									(12,579,000)	(32,406,000)	(14,912,000)
2000 Share Repurchase Program [Member]
Treasury Stock, Value, Acquired, Cost Method											419,200,000
Stock Repurchase Program, Authorized Amount												3,000,000,000
2012 Share Repurchase Program [Member]
Treasury Stock, Value, Acquired, Cost Method										1,100,000,000	400,000,000
Stock Repurchase Program, Authorized Amount											1,500,000,000
2013 Share Repurchase Program [Member]
Treasury Stock, Value, Acquired, Cost Method									800,000,000	500,000,000
Stock Repurchase Program, Authorized Amount													5,000,000,000
Stock Repurchase Program, Remaining Authorized Repurchase Amount	$ 3,700,000,000								$ 3,700,000,000