Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Dilutive Impact of Common Stock Equivalents on Earnings per Share (Abstract]
Net income	$ 241,312	$ 152,066
Basic earnings per share [Abstract]
Earnings available to common shareholders	$ 241,312	$ 152,066
Weighted average common shares outstanding - basic (in shares)	508,667	506,983
Earnings available to common shareholders - basic (in dollars per share)	$ 0.47	$ 0.30
Effect of dilutive securities [Abstract]
Time based equity awards (in shares)	483	410
Diluted earnings per share [Abstract]
Earnings available to common shareholders	$ 241,312	$ 152,066
Weighted average common shares outstanding - diluted (in shares)	509,150	507,393
Earnings available to common shareholders - diluted (in dollars per share)	$ 0.47	$ 0.30