Consolidated Statements of Shareholders' Equity (USD $) In Millions, unless otherwise specified	Total	Common Shares	Paid-in Capital in Excess of Par Value	Treasury Stock	Retained Earnings	Accumulated Other Comprehensive Income (Loss)	Noncontrolling interest in Consolidated Subsidiaries
Beginning balance at Dec. 31, 2011	$ (13,216)	$ (2,683)	$ (455)	$ (4,547)	$ (14,880)	$ 273	$ (18)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	2,645	0	0	0	2,635	0	10
Other Comprehensive Income (Loss), Net of Tax	(36)	0	0	0	0	(36)	0
Cash dividends	(333)	0	0	0	(333)	0
Noncontrolling Interest, Decrease from Distributions to Noncontrolling Interest Holders							0
Stock Issued During Period, Value, Share-based Compensation, Net of Forfeitures	295	(1)	25	271	0	0	0
Other	3	0	6	0	0	0	(3)
Ending balance at Dec. 31, 2012	(15,790)	(2,682)	(486)	(4,276)	(17,182)	309	(25)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	2,135	0	0	0	2,125	0	10
Other Comprehensive Income (Loss), Net of Tax	2	0	0	0	0	2	0
Treasury Stock, Value, Acquired, Cost Method	(4,356)	0	0	(4,356)	0	0	0
Cash dividends	(465)	0	0	0	(465)	0
Noncontrolling Interest, Decrease from Distributions to Noncontrolling Interest Holders							0
Stock Issued During Period, Value, Share-based Compensation, Net of Forfeitures	484	2	97	583	0	0	0
Other	25	0	26	0	0	0	(1)
Ending balance at Dec. 31, 2013	(13,615)	(2,680)	(415)	(8,049)	(18,842)	307	(34)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	3,501	0	0	0	3,500	0	1
Other Comprehensive Income (Loss), Net of Tax	(92)	0	0	0	0	(92)	0
Treasury Stock, Value, Acquired, Cost Method	(800)	0	0	(800)	0	0	0
Cash dividends	(533)	0	0	0	(533)	0
Noncontrolling Interest, Decrease from Distributions to Noncontrolling Interest Holders							0
Stock Issued During Period, Value, Share-based Compensation, Net of Forfeitures	556	1	161	718	0	0	0
Other	(51)	0	55	0	0	0	(4)
Ending balance at Dec. 31, 2014	$ (16,298)	$ (2,679)	$ (309)	$ (8,131)	$ (21,809)	$ 399	$ (31)