Consolidated Statements Of Stockholders' Equity - USD ($) shares in Thousands, $ in Millions	Total	Additional Paid-in Capital [Member]	Treasury Stock [Member]	Common Stock [Member]	Accumulated Deficit	AOCI Attributable to Parent [Member]
Comprehensive income (loss):
Shares, Issued			(31,400)	(137,100)
Stock Issued During Period, Value, Stock Options Exercised	$ 0.0	$ (3.0)	$ (3.0)
Excess Tax Benefit from Share-based Compensation, Financing Activities	(7.0)	7.0	0.0
Stock Issued During Period, Value, Employee Stock Purchase Plan	0.0	(1.0)	(1.0)
Balance at Dec. 31, 2014	(665.0)	(7,212.0)	$ 4,411.0	$ (1.0)	$ 2,115.0	$ (22.0)
Comprehensive income (loss):
Net income	313.0				313.0
Other comprehensive income (loss)	(125.0)					(125.0)
Number of Options - Exercised			0
Treasury Stock, Shares, Acquired			8,800
Treasury Stock, Value, Acquired, Cost Method	(394.0)		$ (394.0)
Balance at Dec. 31, 2015	(439.0)	(7,010.0)	4,623.0	(1.0)	1,802.0	147.0
Comprehensive income (loss):
Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest	188.0
Stock Issued During Period, Value, Restricted Stock Award, Net of Forfeitures	(13.0)	(191.0)	$ 178.0
Stock Issued During Period, Shares, Restricted Stock Award, Net of Forfeitures			900
Balance at Dec. 31, 2014	$ (665.0)	(7,212.0)	$ 4,411.0	(1.0)	2,115.0	(22.0)
Comprehensive income (loss):
Treasury Stock, Shares, Acquired	27,000
Treasury Stock, Value, Acquired, Cost Method	$ (1,000.0)
Balance at Dec. 31, 2017	(573.0)	(6,820.0)	$ 5,002.0	$ (1.0)	1,222.0	24.0
Comprehensive income (loss):
Shares, Issued			(39,300)	(137,100)
Stock Issued During Period, Value, Stock Options Exercised	0.0	(2.0)	$ (2.0)
Excess Tax Benefit from Share-based Compensation, Financing Activities	5.0	5.0	0.0
Stock Issued During Period, Value, Employee Stock Purchase Plan	(1.0)	1.0	(2.0)
Balance at Dec. 31, 2015	(439.0)	(7,010.0)	$ 4,623.0	$ (1.0)	1,802.0	147.0
Comprehensive income (loss):
Net income	163.0				163.0
Other comprehensive income (loss)	(7.0)					(7.0)
Number of Options - Exercised			0
Treasury Stock, Shares, Acquired			12,300
Treasury Stock, Value, Acquired, Cost Method	(390.0)		$ (390.0)
Balance at Dec. 31, 2016	(221.0)	(6,918.0)	4,905.0	$ (1.0)	1,639.0	154.0
Comprehensive income (loss):
Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest	156.0
Stockholders' Equity Attributable to Noncontrolling Interest	5.0	5.0
Stock Issued During Period, Value, Restricted Stock Award, Net of Forfeitures	15.0	(89.0)	$ 104.0
Stock Issued During Period, Shares, Restricted Stock Award, Net of Forfeitures			500
Shares, Issued			(51,100)	(137,100)
Stock Issued During Period, Value, Stock Options Exercised	0.0	(48.0)	$ (48.0)
Stock Issued During Period, Value, Employee Stock Purchase Plan	0.0	1.0	$ (1.0)
Net income	361.0
Other comprehensive income (loss)	$ 130.0
Number of Options - Exercised	537		500
Treasury Stock, Shares, Acquired			6,100
Treasury Stock, Value, Acquired, Cost Method	$ (200.0)		$ (200.0)
Balance at Dec. 31, 2017	(573.0)	(6,820.0)	5,002.0	$ (1.0)	1,222.0	$ 24.0
Comprehensive income (loss):
Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest	491.0
Stockholders' Equity Attributable to Noncontrolling Interest	1.0	1.0
Stock Issued During Period, Value, Restricted Stock Award, Net of Forfeitures	4.0	$ (50.0)	$ 54.0
Stock Issued During Period, Shares, Restricted Stock Award, Net of Forfeitures			400
Cumulative Effect of New Accounting Principle in Period of Adoption	$ 56.0				$ 56.0
Shares, Issued			(56,300)	(137,100)