Stock-based Compensation - Schedule of Stock Options Roll Forward (Details) $ / shares in Units, shares in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2015 USD ($) $ / shares shares
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Beginning balance | shares	17.1
Granted | shares	1.3
Exercised | shares	(7.3)
Forfeited | shares	(0.1)
Ending balance | shares	11.0
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Abstract]
Beginning balance (in dollars per share) | $ / shares	$ 9.38
Granted (in dollars per share) | $ / shares	31.61
Exercised (in dollars per share) | $ / shares	8.97
Forfeited (in dollars per share) | $ / shares	17.07
Ending balance (in dollars per share) | $ / shares	$ 12.19
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest [Abstract]
Vested and expected to vest, shares | shares	11.0
Vested and expected to vest, weighted average exercise price (in dollars per share) | $ / shares	$ 12.19
Vested and expected to vest, aggregate intrinsic value | $	$ 165.8
Vested and expected to vest, weighted average remaining contractual term	7 years 9 months 22 days
Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract]
Exercisable, shares | shares	9.8
Exercisable, weighted average exercise price (in dollars per share) | $ / shares	$ 9.68
Exercisable, aggregate intrinsic value | $	$ 165.6
Exercisable, weighted average remaining contractual term	7 years 7 months 10 days