Stock-Based Compensation Plans (Details)	12 Months Ended
	Dec. 31, 2015 USD ($) compensation_plan $ / shares shares	Dec. 31, 2014 USD ($) $ / shares shares	Dec. 31, 2013 USD ($) $ / shares shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of equity compensation plans currently available for future grants | compensation_plan	1
Total stock-based compensation expense | $	$ 49,000,000	$ 54,000,000	$ 54,000,000
Recognized tax benefit | $	$ 18,000,000	$ 20,000,000	$ 20,000,000
Summary of option activity [Rollforward]
Outstanding at beginning of period (in shares) | shares	3,912,488
Granted (in shares) | shares	620,968
Exercised (in shares) | shares	(771,707)
Forfeited and expired (in shares) | shares	(37,603)
Outstanding at end of period (in shares) | shares	3,724,146	3,912,488
Vested or expected to vest at end of period (in shares) | shares	3,710,191
Exercisable at end of period (in shares) | shares	2,377,609
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Abstract]
Weighted average exercise price at beginning of period (in dollars per share) | $ / shares	$ 51.89
Weighted average exercise price granted (in dollars per share) | $ / shares	65.2
Weighted average exercise price per exercised (in dollars per share) | $ / shares	40.39
Weighted average exercise price forfeited and expired (in dollars per share) | $ / shares	59.09
Weighted average exercise price outstanding at end of period (in dollars per share) | $ / shares	56.42	$ 51.89
Weighted average exercise price vested or expected to vest at end of period (in dollars per share) | $ / shares	56.40
Weighted average exercise price exercisable at end of period (in dollars per share) | $ / shares	$ 53.07
Weighted average remaining contractual term outstanding at end of period (in years)	6 years 9 months 7 days
Weighted average remaining contractual term vested or expected to vest at end of period (in years)	6 years 9 months 4 days
Weighted average remaining contractual term exercisable at end of period (In years)	5 years 5 months 27 days
Aggregate intrinsic value outstanding at end of period | $	$ 28,000,000
Aggregate intrinsic value vested or expected to vest at end of period | $	28,000,000
Aggregate intrinsic value exercisable at end of period | $	$ 25,000,000
Fair values and weighted-average assumptions used to value options [Abstract]
Expected life (in years)	3 years 6 months	3 years 3 months 18 days	3 years 2 months 12 days
Risk-free interest rate (in hundredths)	0.95%	0.86%	0.67%
Volatility (in hundredths)	27.90%	33.80%	34.30%
Expected dividend yield (in hundredths)	0.00%	0.00%	0.00%
Grant-date fair value per option (in dollars per share) | $ / shares	$ 14.47	$ 14.51	$ 16.19
Intrinsic value of options exercised (dollars in millions) | $	$ 16,000,000	$ 26,000,000	$ 31,000,000
Average intrinsic value per share of options exercised (in dollars per share) | $ / shares	$ 21.31	$ 24.17	$ 26.30
Restricted and deferred stock units and awards [Abstract]
Annual value of deferred stock units available for grants to non-employee directors | $	$ 250,000
Period of time after the date of grant during which deferred stock units cannot be converted into common stock	3 years
Restricted and deferred stock units and awards activity [Roll Forward]
Shares granted (in shares) | shares	1,183,828	826,329	838,207
Intrinsic value of units vesting (dollars in millions) | $	$ 39,000,000	$ 34,000,000	$ 46,000,000
Restricted and deferred stock units and awards, additional disclosures [Abstract]
Weighted average grant date fair value, granted (in dollars per share) | $ / shares	$ 54.95	$ 59.63	$ 57.95
Shares reserved for future grants of options, deferred stock units, restricted stock units and other awards (in shares) | shares	9,236,764
Restricted and Deferred Stock Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock-based compensation expense | $	$ 40,000,000	$ 44,000,000	$ 40,000,000
Unrecognized share-based compensation cost [Abstract]
Stock-based compensation cost not yet recognized under the straight-line method (dollars in millions) | $	$ 64,000,000
Weighted-average remaining expense recognition period (in years)	1 year 9 months 18 days
Restricted and deferred stock units and awards activity [Roll Forward]
Nonvested shares, beginning of period (in shares) | shares	1,848,682
Shares granted (in shares) | shares	1,183,828
Shares vested (in shares) | shares	(780,163)
Shares forfeited (in shares) | shares	(86,910)
Nonvested shares, end of period (in shares) | shares	2,165,437	1,848,682
Restricted and deferred stock units and awards, additional disclosures [Abstract]
Weighted average grant date fair value, outstanding, beginning of period (in dollars per share) | $ / shares	$ 56.85
Weighted average grant date fair value, granted (in dollars per share) | $ / shares	54.95
Weighted average grant date fair value, vested (in dollars per share) | $ / shares	54.79
Weighted average grant date fair value, forfeited (in dollars per share) | $ / shares	54.25
Weighted average grant date fair value, outstanding at end of period (in dollars per share) | $ / shares	$ 56.66	$ 56.85
Restricted and Deferred Stock Units | Incremental Vesting
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
The incremental portion of options that vest annually on the anniversary date of grant	33.33%
Restricted and Deferred Stock Units | Cliff Vesting
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
The incremental portion of options that vest annually on the anniversary date of grant	100.00%
Restricted and deferred stock units and awards [Abstract]
Award vesting period	3 years
Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock-based compensation expense | $	$ 9,000,000	$ 10,000,000	$ 14,000,000
The incremental portion of options that vest annually on the anniversary date of grant	33.33%
Unrecognized share-based compensation cost [Abstract]
Stock-based compensation cost not yet recognized under the straight-line method (dollars in millions) | $	$ 15,000,000
Weighted-average remaining expense recognition period (in years)	2 years 2 months 16 days
Stock Options | Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Terms of awards	7 years
Stock Options | Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Terms of awards	10 years
Deferred Stock Units (DSUs) | Incremental Vesting
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
The incremental portion of options that vest annually on the anniversary date of grant	25.00%
Restricted and Deferred Stock Units with Performance Conditions [Member]
Restricted and deferred stock units and awards activity [Roll Forward]
Shares granted (in shares) | shares	214,072	174,697	185,992