Stock-based Compensation (Tables)

6 Months Ended

Jun. 30, 2015

Disclosure of Compensation Related Costs, Share-based Payments [Abstract]

Schedule of Share-based Payment Award, Stock Options, Valuation Assumptions

Principal weighted average assumptions used in applying the Black-Scholes model were as follows:

	2015 Grants		2014 Grants		2013 Grants
Expected Term	6.00 years		7.81 years		7.81 years
Volatility	22.24	%	28.28	%	28.61	%
Dividend Yield	—		—		—
Discount Rate	1.79	%	2.21	%	2.13	%

Schedule of Stock Options Roll Forward

A summary of stock option award activity as of and for the six months ended June 30, 2015, is presented below:

	Awards/Units (millions)		Weighted- Average Exercise Price		Aggregate Intrinsic Value  (millions)		Weighted Average Remaining Contractual Life (years)
Outstanding at January 1, 2015	17.1		$	9.38
Granted	1.2		$	31.91
Exercised	(5.0	)	$	9.45
Forfeited	—		$	—
Outstanding at June 30, 2015	13.3		$	11.34
Vested and expected to vest at June 30, 2015	13.3		$	11.34	$	289.5	8.26
Exercisable at June 30, 2015	12.1		$	9.35	$	288.1	8.11

Schedule of Share-based Compensation, Activity

A summary of restricted stock and restricted stock unit award activity as of June 30, 2015 is presented below:

	Awards (millions)	Weighted-Average Fair Value
Outstanding at January 1, 2015	—	$	—
Granted	1.7	$	32.33
Vested	—	$	—
Forfeited	—	$	—
Outstanding at June 30, 2015	1.7	$	32.33