Stock-Based Compensation (Stock Based Compensation Activity) (Detail) (USD $) In Millions, except Share data in Thousands, unless otherwise specified	3 Months Ended	9 Months Ended	12 Months Ended	9 Months Ended
	Sep. 30, 2014	Sep. 30, 2014	Dec. 31, 2013	Sep. 30, 2014 Time-Based RSUs	Sep. 30, 2013 Time-Based RSUs	Sep. 30, 2014 Performance-Based and Market-Based RSUs	Sep. 30, 2013 Performance-Based and Market-Based RSUs	Sep. 30, 2014 Cash Unit Awards	Sep. 30, 2013 Cash Unit Awards	Sep. 30, 2014 Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Adjustments to Additional Paid in Capital, Income Tax Benefit from Share-based Compensation		$ 48
Number of Options, Balance	858	858	979
Weighted Average Grant Price, Balance				$ 17.92		$ 13.79		$ 14.90
Weighted Average Grant Price, Granted at fair market value				$ 42.05	$ 21.77	$ 42.03	$ 20.03	$ 0.00	$ 17.14
Weighted Average Grant Price, Vested/exercised				$ 16.72		$ 10.91		$ 0.00
Weighted Average Grant Price, Canceled				$ 23.92		$ 20.25		$ 0.00
Weighted Average Grant Price, Balance				$ 27.27		$ 19.19		$ 14.90
Number of RSUs, Balance				1,308		2,043		267
Number of RSUs, Granted at fair market value				381		326		0
Number of RSUs, Vested/exercised				(605)		(436)		0
Number of RSUs, Canceled				(73)		(42)		0
Number of RSUs, Balance				1,011		1,891		267
Options outstanding, intrinsic value	45	45	37
Stock Issued During Period, Value, Restricted Stock Award, Gross	14	15
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Aggregate Intrinsic Value, Outstanding						104		15		56
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized										$ 35
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Remaining Contractual Term	4 years 6 months 0 days		5 years 2 months 0 days			0 years 9 months 0 days