Employee Benefit Plans (Tables)

12 Months Ended

Dec. 31, 2017

Compensation And Retirement Disclosure [Abstract]

Schedule of Fair Value of TSR Performance RSUs

We estimated the fair value of the TSR Performance RSUs referred to above on the date of the grant using a Monte Carlo simulation with the following assumptions:

Volatility of common stock	27.85	%
Expected dividend yield	0.00	%
Risk-free interest rate	2.33	%

Schedule of Non-Vested Stock Awards

A summary of the status of our non-vested stock awards is presented in the table below:

	Shares/Units			Weighted Average Market Value Per Share
Balance at December 31, 2014		7,542,096		$	22.53
Granted		2,195,638			36.80
Vested		(2,033,263	)		21.29
Forfeited		(237,406	)		26.10
Balance at December 31, 2015		7,467,065			29.08
Granted		1,496,408			29.24
Vested		(3,840,379	)		25.09
Forfeited		(279,821	)		28.62
Balance at December 31, 2016		4,843,273			31.66
Granted		5,152,082			40.11
Vested		(2,020,812	)		29.75
Forfeited		(297,441	)		32.85
Balance at December 31, 2017		7,677,102			37.76