Stock-Based Plans - Range of Exercise Prices and Intrinsic Value Related to Options Outstanding (Details 3) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2015 USD ($) $ / shares shares
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range
Number Outstanding (in shares) | shares	3,971,526
Weighted Average Remaining Contractual Life	6 years 8 months 12 days
Weighted Average Exercise Price (in dollars per share)	$ 62.25
Options exercisable (in shares) | shares	2,331,002
Weighted Average Remaining Contractual Life, Exercisable	5 years 4 months 24 days
Weighted Average Exercise Price Per Share (in dollars per share)	$ 60.53
Options outstanding, aggregate intrinsic value | $	$ 4
Options exercisable, aggregate intrinsic value | $	$ 4
$30.46 - $41.77
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range
Range of Exercise Prices, low end of range (in dollars per share)	$ 30.46
Range of Exercise Prices, high end of range (in dollars per share)	$ 41.77
Number Outstanding (in shares) | shares	152,128
Weighted Average Remaining Contractual Life	3 years 2 months 12 days
Weighted Average Exercise Price (in dollars per share)	$ 30.46
Options exercisable (in shares) | shares	152,128
Weighted Average Remaining Contractual Life, Exercisable	3 years 2 months 12 days
Weighted Average Exercise Price Per Share (in dollars per share)	$ 30.46
$42.11 - $62.50
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range
Range of Exercise Prices, low end of range (in dollars per share)	42.11
Range of Exercise Prices, high end of range (in dollars per share)	$ 62.50
Number Outstanding (in shares) | shares	2,595,955
Weighted Average Remaining Contractual Life	7 years 1 month 6 days
Weighted Average Exercise Price (in dollars per share)	$ 58.20
Options exercisable (in shares) | shares	1,381,995
Weighted Average Remaining Contractual Life, Exercisable	5 years 8 months 12 days
Weighted Average Exercise Price Per Share (in dollars per share)	$ 56.95
$68.36 - $80.12
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range
Range of Exercise Prices, low end of range (in dollars per share)	68.36
Range of Exercise Prices, high end of range (in dollars per share)	$ 80.12
Number Outstanding (in shares) | shares	1,223,443
Weighted Average Remaining Contractual Life	6 years 3 months 18 days
Weighted Average Exercise Price (in dollars per share)	$ 74.81
Options exercisable (in shares) | shares	796,879
Weighted Average Remaining Contractual Life, Exercisable	5 years 3 months 18 days
Weighted Average Exercise Price Per Share (in dollars per share)	$ 72.47