Stock-Based Compensation (Stock Options Outstanding, Exercisable and Activity) (Detail) (USD $) In Millions, except Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013
Number of Shares
Beginning Balance	2,644,388
Granted	362,721
Exercised	(758,299)
Forfeited/Expired	(27,629)
Ending Balance	2,221,181	2,644,388
Vested or expected to vest, at end of period	2,171,513
Exercisable, at end of period	641,592
Weighted Average Exercise Price
Beginning Balance (in dollars per share)	$ 88.08
Granted (in dollars per share)	$ 187.21
Exercised (in dollars per share)	$ 75.18
Forfeited/Expired (in dollars per share)	$ 140.54
Ending Balance (in dollars per share)	$ 108.01	$ 88.08
Vested or expected to vest, at end of period (in dollars per share)	$ 107.71
Exercisable, at end of period (in dollars per share)	$ 66.79
Weighted Average Remaining Contractual Life (in years)
Outstanding	6 years 9 months 10 days	6 years 11 months 0 days
Vested or expected to vest, at end of period	6 years 9 months 5 days
Exercisable, at end of period	4 years 0 months 15 days
Intrinsic Value (in millions)
Outstanding	$ 273	$ 269
Vested or expected to vest, at end of period	268
Exercisable, at end of period	$ 105