Income Per Share (Details) (USD $) In Thousands, except Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Basic:
Net income	$ 440,065	$ 556,807	$ 770,711
Basic weighted shares outstanding (in shares)	320,195,000	320,830,000	321,892,000
Net income per share (in dollars per share)	$ 1.37	$ 1.74	$ 2.39
Diluted:
Net income	$ 440,065	$ 556,807	$ 770,711
Basic weighted shares outstanding (in shares)	320,195,000	320,830,000	321,892,000
Stock options, ESPP and restricted stock unit shares (in shares)	2,823,000	3,667,000	5,714,000
Diluted weighted shares outstanding	323,018,000	324,497,000	327,606,000
Net income per share (in dollars per share)	$ 1.36	$ 1.72	$ 2.35
Antidilutive Securities Excluded from Computation of Earning Per Share, Amount	2,000,000	1,800,000	1,800,000