Earnings Per Share (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Dilutive Impact of Common Stock Equivalents on Earnings per Share (Abstract]
Net income	$ 261,221	$ 236,570
Basic earnings per share [Abstract]
Earnings available to common shareholders	261,221	236,570
Weighted average common shares outstanding - basic (in shares)	499,523	489,781
Earnings available to common shareholders - basic (in dollars per share)	$ 0.52	$ 0.48
Effect of dilutive securities [Abstract]
Time based equity awards	223	750
Diluted earnings per share [Abstract]
Earnings available to common shareholders	$ 261,221	$ 236,570
Weighted average common shares outstanding - diluted (in shares)	499,746	490,531
Earnings available to common shareholders - diluted (in dollars per share)	$ 0.52	$ 0.48