Stock-Based Compensation (Stock Based Compensation Activity) (Detail) (USD $) In Millions, except Share data in Thousands, unless otherwise specified	3 Months Ended			6 Months Ended		12 Months Ended	6 Months Ended
	Jun. 30, 2014		Mar. 31, 2013	Jun. 30, 2014		Dec. 31, 2013	Jun. 30, 2014 Time-Based RSUs		Jun. 30, 2013 Time-Based RSUs	Jun. 30, 2014 Performance-Based and Market-Based RSUs		Jun. 30, 2013 Performance-Based and Market-Based RSUs	Jun. 30, 2014 Cash Unit Awards		Jun. 30, 2013 Cash Unit Awards	Jun. 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				$ 52
Number of Options, Balance	879	[1]		879	[1]	979
Weighted Average Grant Price, Balance							$ 17.92	[2]		$ 13.79	[2]		$ 14.90	[2]
Weighted Average Grant Price, Granted at fair market value							$ 41.94		$ 21.73	$ 41.97		$ 20.64	$ 0.00		$ 17.14
Weighted Average Grant Price, Vested/exercised							$ 16.71	[3]		$ 10.91	[3]		$ 0.00	[3]
Weighted Average Grant Price, Canceled							$ 23.62			$ 21.48			$ 0.00
Weighted Average Grant Price, Balance							$ 27.12	[4]		$ 19.13	[4]		$ 14.90	[4]
Number of RSUs, Balance							1,308	[2]		2,043	[2]		267	[2]
Number of RSUs, Granted at fair market value							379			325			0
Number of RSUs, Vested/exercised							(600)	[3]		(432)	[3]		0	[3]
Number of RSUs, Canceled							(57)			(32)			0
Number of RSUs, Balance							1,030	[4]		1,904	[4]		267	[4]
Options outstanding, intrinsic value	50	[1]		50	[1]	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										114			16			61
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized																$ 41
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Remaining Contractual Term	4 years 8 months 0 days	[1]				5 years 2 months 0 days				1 year 1 month 0 days

[1] The Company assumes that substantially all outstanding stock options will vest over time.

[2] Reflects the maximum number of stock units assuming achievement of all time-, performance- and market-vesting criteria and does not include those for non-employee directors. The weighted-average fair value of time-based RSUs, performance-based and market-based RSUs, and cash units granted in 2013 was $21.73, $20.64 and $17.14, respectively.

[3] The total grant date fair value of RSUs vested during the six months ended June 30, 2014 and 2013 was $15 million and $14 million, respectively.

[4] The Company’s outstanding time-based RSUs, performance-based and market-based RSUs, and cash units had aggregate intrinsic value of $61 million, $114 million and $16 million, respectively. Aggregate unrecognized compensation expense related to time-based RSUs and performance-based and market-based RSUs amounted to $41 million and will be recognized over a weighted average vesting period of 1.1 years. The Company assumes that substantially all outstanding awards will vest over time.