Stock-Based Compensation - Additional Information (Detail) - USD ($)		12 Months Ended
	Apr. 30, 2002	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Vesting period of performance shares		3 years
Shares granted during the period		1,000,000
Weighted average grant date fair value		$ 79.55
Shares forfeited		200,000
Weighted average fair value of shares forfeited		$ 72.75
Shares remained outstanding		2,100,000	2,600,000
Shares remained outstanding with a weighted average fair value		$ 72.79	$ 65.28
Stock-based compensation expense		$ 56,000,000	$ 52,000,000	$ 54,000,000
Tax benefits from compensation expense		22,000,000	$ 20,000,000	$ 21,000,000
Unrecognized compensation cost, net of estimated forfeitures		$ 58,000,000
Weighted-average period of unrecognized compensation cost, expected to be recognized		1 year 4 months 24 days
Stock options granted		0	0	0
Performance Shares [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Shares forfeited		67,000	39,000
Weighted average fair value of shares forfeited		$ 94.86	$ 89.86
Shares remained outstanding		358,000	302,000
Shares remained outstanding with a weighted average fair value		$ 90.24
Shares remaining life		1 year
2002 Employee Stock Purchase Plan [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Shares reserved for issuance under the ESPP	12,000,000
Eligibility of employee continuous service period		30 days
Maximum employees contribution allowed to the ESPP as a percentage of total cash compensation	20.00%
Employee accumulated period to purchase shares	3 months
Maximum value of shares that may be purchased by participant under ESPP	$ 25,000
Purchase price to employees under ESPP, equal to fair market value of shares	95.00%
Shares issued under the ESPP		100,000	100,000
Share purchase price under ESPP, lower range		$ 67.90	$ 75.05
Share purchase price under ESPP, upper range		$ 78.62	$ 80.31
2004 Long-Term Incentive Compensation Plan [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Additional awards granted		0
Historical share price volatility period and contractual term		8 years
Total non-vested options			100,000
Weighted average grant date fair value for non-vested options			$ 19.52
Non-vested options vested in period		100,000
Weighted average grant date fair value for non-vested options vested		$ 19.94
Total intrinsic value of options exercised		$ 8,000,000	$ 18,000,000	$ 104,000,000
Tax benefits from stock options exercised		$ 3,000,000	$ 7,000,000	$ 32,000,000
Service period for options		4 years
Aggregate intrinsic value of outstanding options		$ 6,000,000
Aggregate intrinsic value of exercisable options		$ 5,000,000
Weighted-average contractual life for outstanding options		2 years 7 months 6 days
Weighted-average contractual life for exercisable options		2 years 3 months 18 days
2013 Long-Term Incentive Compensation Plan [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Aggregate number of shares available for grant		10,300,000
2013 Long-Term Incentive Compensation Plan [Member] | Performance Shares [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Shares granted during the period		124,000	177,000
Weighted average grant date fair value		$ 90.03	$ 103.65
2013 Long-Term Incentive Compensation Plan [Member] | Restricted stock and restricted stock units [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Shares granted during the period		1,000,000
Weighted average grant date fair value		$ 79.55	$ 81.75	$ 60.38
Service period for options		3 years
Fair value of restricted stock and units for which restrictions lapsed		$ 104,000,000	$ 91,000,000	$ 103,000,000