Common Stock - Additional Information (Details) - USD ($)		1 Months Ended		3 Months Ended							9 Months Ended		45 Months Ended
	Feb. 01, 2017	Feb. 28, 2017	Jan. 31, 2015	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Dec. 31, 2017	Oct. 31, 2015
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Impact of earnings per share, basic and diluted (in dollars per share)					$ 0			$ 0			$ 0	$ 0.01
Stock-based compensation					$ 5,000,000			$ 1,000,000			$ 12,000,000	$ 12,000,000
Tax benefit from options exercised											1,000,000	2,000,000
Total fair value of shares vested											$ 0	2,000,000
Treasury stock repurchased					14,592,888						14,592,888		14,592,888	14,592,888
Dividend declared (in dollars per share)	$ 0.25
Annual divided declared (in dollars per share)	$ 1.00
Dividend paid (in dollars per share)					$ 0.25	$ 0.25	$ 0.25	$ 0.25	$ 0.25	$ 0.25
Cash dividends paid					$ 14,000,000			$ 14,000,000			$ 39,000,000	40,000,000
Equity Option
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Compensation expense					0			0			0	1,000,000
Stock Option
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Cash received from stock option exercises											1,000,000	7,000,000
Restricted Stock, Restricted Stock Units, Long Term Performance Units, SARs
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Unrecognized compensation costs					3,000,000						$ 3,000,000		$ 3,000,000
Unrecognized compensation costs, not yet recognized											1 year 2 months 12 days
Stock-based compensation					3,000,000			$ 2,000,000			$ 7,000,000	10,000,000
Restricted Shares
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Unrecognized compensation costs					4,000,000						$ 4,000,000		4,000,000
Unrecognized compensation costs, not yet recognized											1 year 2 months 12 days
Total fair value of restricted shares vested											$ 11,000,000	$ 14,000,000
Share-Settled RSUs
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Unrecognized compensation costs					10,000,000						$ 10,000,000		10,000,000
Unrecognized compensation costs, not yet recognized											2 years 4 months 24 days
Vesting period											3 years
PSUs
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Unrecognized compensation costs					$ 8,000,000						$ 8,000,000		$ 8,000,000
Unrecognized compensation costs, not yet recognized											2 years 4 months 24 days
Vesting period											3 years
Common Stock
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Amount authorized to repurchase		$ 400,000,000	$ 350,000,000												$ 200,000,000
Period of time to repurchase common stock		3 years	3 years
Previous authorized amount to repurchase		$ 112,000,000
Number of shares repurchased													11,300,000.0
Value of shares reprchased													$ 607,000,000
Forecast
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Cash dividends paid				$ 20,000,000