Stock-based Compensation (Tables)

6 Months Ended

Jun. 30, 2017

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

Schedule of Stock Options Roll Forward

A summary of stock option award activity as of and for the six months ended June 30, 2017 is presented below.

Stock Options	Awards/Units (in millions)		Weighted- Average Exercise Price		Aggregate Intrinsic Value  (in millions)		Weighted Average Remaining Contractual Life (years)
Outstanding at January 1, 2017	9.6		$	14.40
Granted	0.9		$	29.52
Exercised	(1.2	)	$	10.54
Forfeited	(0.1	)	$	28.10
Outstanding at June 30, 2017	9.2		$	16.23
Vested and expected to vest at June 30, 2017	9.2		$	16.23	$	145.1	6.91
Exercisable at June 30, 2017	7.2		$	13.15	$	136.5	6.37

Schedule of Restricted Stock Units and Restricted Stock Awards Roll Forward

Restricted Stock Awards and Restricted Stock Units	Awards (millions)		Weighted-Average Fair Value
Outstanding at January 1, 2017	2.3		$	29.18
Granted	0.7		$	30.17
Vested	(0.9	)	$	30.05
Forfeited	(0.1	)	$	26.26
Outstanding at June 30, 2017	2.0		$	29.14

Schedule of Performance Stock Roll Forward

Performance Stock Awards and Performance Share Units	Awards (millions)	Weighted-Average Fair Value
Outstanding at January 1, 2017	0.3	$	27.74
Granted	0.3	$	38.11
Vested	—	$	—
Forfeited	—	$	—
Outstanding at June 30, 2017	0.6	$	31.11