Condensed Consolidated Statement of Shareholders' Equity Dividend per share - USD ($)	Total	Common Stock [Member]	Retained Earnings [Member]	AOCI Attributable to Parent [Member]	Additional Paid-in Capital [Member]
Common Stock, Shares, Outstanding	271,852,000
Common Stock, Value, Issued		$ 272,000
Additional Paid in Capital	$ 0
Retained Earnings (Accumulated Deficit)			$ 1,856,358,000
Accumulated Other Comprehensive Income (Loss), Net of Tax	(11,354,000)			$ (11,354,000)
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest	1,845,276,000
Dividends	1.44
Net income	447,396,000
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest	447,396,000
Other Comprehensive Income (Loss), Net of Tax	(1,295,000)			(1,295,000)
Shares of common stock repurchased		(6,296,000)
Treasury Stock, Value, Acquired, Par Value Method	(358,512,000)	$ 5,000	280,272,000		$ 78,235,000
Cumulative-effect adjustment for adoption of ASU 2016-02	(2,053,000)		(2,053,000)
Stock Issued During Period, Shares, Restricted Stock Award, Net of Forfeitures		1,017,000
Stock Issued During Period, Value, Restricted Stock Award, Net of Forfeitures	16,630,000				(29,136,000)
Adjustment to Retained Earnings ASU 2016-01	(29,136,000)
Stock Issued During Period, Shares, Other		588,000
Stock Issued During Period, Value, Stock Options Exercised	72,206,000				16,630,000
APIC, Share-based Payment Arrangement, Increase for Cost Recognition					72,206,000
APIC, Share-based Payment Arrangement, ESPP, Increase for Cost Recognition					18,535,000
Stock Issued During Period, Shares, Employee Stock Purchase Plans		402,000
Stock Issued During Period, Value, Employee Stock Purchase Plan					18,535,000
Dividends, Common Stock, Cash	$ (389,104,000)		(389,104,000)
Common Stock, Shares, Outstanding	269,743,000
Common Stock, Value, Issued		$ 270,000
Additional Paid in Capital	$ 0
Retained Earnings (Accumulated Deficit)			1,737,528,000
Accumulated Other Comprehensive Income (Loss), Net of Tax				(11,289,000)
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest	1,726,509,000
Dividends	0.48
Net income	161,190,000
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest	161,190,000
Other Comprehensive Income (Loss), Net of Tax	(1,360,000)			(1,360,000)
Shares of common stock repurchased		(2,812,000)
Treasury Stock, Value, Acquired, Par Value Method	(157,003,000)	$ 3,000	137,321,000		19,679,000
Stock Issued During Period, Shares, Restricted Stock Award, Net of Forfeitures		360,000
Stock Issued During Period, Value, Restricted Stock Award, Net of Forfeitures	7,810,000				(11,570,000)
Adjustment to Retained Earnings ASU 2016-01	(11,570,000)
Stock Issued During Period, Shares, Other		272,000
Stock Issued During Period, Value, Stock Options Exercised	23,439,000				7,810,000
APIC, Share-based Payment Arrangement, Increase for Cost Recognition					23,439,000
Dividends, Common Stock, Cash	$ (129,072,000)		(129,072,000)
Common Stock, Shares, Outstanding	267,563,000
Common Stock, Value, Issued		$ 267,000
Additional Paid in Capital	$ 0
Retained Earnings (Accumulated Deficit)			1,632,325,000
Accumulated Other Comprehensive Income (Loss), Net of Tax	12,649,000			(12,649,000)
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest	$ 1,619,943,000
Common Stock, Shares, Outstanding	266,797,000
Common Stock, Value, Issued	$ 266,000	$ 266,000
Additional Paid in Capital	0
Retained Earnings (Accumulated Deficit)			1,671,786,000
Accumulated Other Comprehensive Income (Loss), Net of Tax	(14,595,000)			(14,595,000)
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest	1,657,457,000
Dividends	0.48
Net income	573,522,000
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest	573,522,000
Other Comprehensive Income (Loss), Net of Tax	(1,470,000)			(1,470,000)
Shares of common stock repurchased		(150,000)
Treasury Stock, Value, Acquired, Par Value Method	(9,201,000)		0		9,201,000
Stock Issued During Period, Shares, Restricted Stock Award, Net of Forfeitures		1,224,000
Stock Issued During Period, Value, Restricted Stock Award, Net of Forfeitures	2,883,000				(51,916,000)
Adjustment to Retained Earnings ASU 2016-01	(51,916,000)
Stock Issued During Period, Shares, Other		102,000
Stock Issued During Period, Value, Stock Options Exercised	87,539,000				2,883,000
APIC, Share-based Payment Arrangement, Increase for Cost Recognition					87,539,000
APIC, Share-based Payment Arrangement, ESPP, Increase for Cost Recognition		$ 2,000			18,496,000
Stock Issued During Period, Shares, Employee Stock Purchase Plans		391,000
Stock Issued During Period, Value, Employee Stock Purchase Plan					18,498,000
Dividends, Common Stock, Cash	$ (128,147,000)		(128,147,000)
Common Stock, Shares, Outstanding	268,032,000
Common Stock, Value, Issued		$ 268,000
Additional Paid in Capital	$ 42,963,000
Retained Earnings (Accumulated Deficit)			1,897,098,000
Accumulated Other Comprehensive Income (Loss), Net of Tax				(14,268,000)
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest	1,926,061,000
Dividends	0
Net income	220,063,000
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest	220,063,000
Other Comprehensive Income (Loss), Net of Tax	(1,797,000)			(1,797,000)
Stock Issued During Period, Shares, Restricted Stock Award, Net of Forfeitures		330,000
Stock Issued During Period, Value, Restricted Stock Award, Net of Forfeitures	76,000				(15,932,000)
Adjustment to Retained Earnings ASU 2016-01	(15,932,000)
Stock Issued During Period, Shares, Other		2,000
Stock Issued During Period, Value, Stock Options Exercised	$ 20,694,000				76,000
APIC, Share-based Payment Arrangement, Increase for Cost Recognition					$ 20,694,000
Common Stock, Shares, Outstanding	268,364,000
Common Stock, Value, Issued	$ 268,000	$ 268,000
Additional Paid in Capital	47,801,000
Retained Earnings (Accumulated Deficit)			$ 2,117,161,000
Accumulated Other Comprehensive Income (Loss), Net of Tax	(16,065,000)			$ (16,065,000)
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest	$ 2,149,165,000