Statement of Changes in Total Equity (USD $) In Millions, unless otherwise specified	Total	Shareholders' Equity [Member]	Common Stock [Member]	Additional Paid In Capital [Member]	Accumulated Other Comprehensive Income [Member]	Retained Earnings [Member]	Treasury Stock [Member]	Noncontrolling Interest [Member]
Beginning Balance at Dec. 31, 2012	$ 114
Total Equity, beginning of period at Dec. 31, 2012	9,769	9,769	92	3,295	(671)	12,330	(5,277)	0
Increase (Decrease) In Stockholders' Equity [Roll Forward]
Effect of issuing stock for employee benefit plans	27	27		10		(48)	65
Other comprehensive income (loss)	(85)	(85)			(85)
Net income	57	57				57
Common dividends declared (per share: $0.04)	(11)	(11)				(11)
Repurchase of common stock	(97)	(97)					(97)
Redeemable Noncontrolling Interest [Roll Forward]
Other comprehensive income (loss)	(3)
Net income	2
Ending Balance at Mar. 31, 2013	113
Total Equity, end of period at Mar. 31, 2013	9,660	9,660	92	3,305	(756)	12,328	(5,309)	0
Beginning Balance at Dec. 31, 2013	96
Total Equity, beginning of period at Dec. 31, 2013	10,581	10,567	92	3,356	(520)	13,676	(6,037)	14
Increase (Decrease) In Stockholders' Equity [Roll Forward]
Effect of issuing stock for employee benefit plans	28	28		36		(57)	49
Other comprehensive income (loss)	88	87			87			1
Net income	526	528				528		(2)
Common dividends declared (per share: $0.04)	(11)	(11)				(11)
Repurchase of common stock	(643)	(643)					(643)
Redeemable Noncontrolling Interest [Roll Forward]
Other comprehensive income (loss)	(3)
Net income	3
Ending Balance at Mar. 31, 2014	96
Total Equity, end of period at Mar. 31, 2014	$ 10,569	$ 10,556	$ 92	$ 3,392	$ (433)	$ 14,136	$ (6,631)	$ 13