Stockholders' Equity - Capital Stock, Cash Dividend and Share Repurchases (Details)			3 Months Ended			9 Months Ended
	Feb. 13, 2019 $ / shares	Jan. 15, 2019 USD ($)	Dec. 31, 2018 USD ($) $ / shares shares	Sep. 30, 2018 USD ($) $ / shares	Jun. 30, 2018 $ / shares	Dec. 31, 2018 USD ($) vote $ / shares shares	Dec. 31, 2017 USD ($)	Jun. 01, 2018 USD ($)
Class of Stock [Line Items]
Common stock, authorized (in shares) | shares			750,000,000			750,000,000
Common stock, par value (in dollars per share) | $ / shares			$ 0.01			$ 0.01
Preferred stock, authorized (in shares) | shares			1,000,000			1,000,000
Preferred stock, par value (in dollars per share) | $ / shares			$ 0.01			$ 0.01
Number of votes per common share | vote						1
Amount of cash dividend declared						$ 25,000,000
Payments of dividends						$ 17,000,000	$ 0
Cash dividend per common share (in dollars per share) | $ / shares			$ 0.05	$ 0.05	$ 0.05
Amount authorized in share repurchase program								$ 400,000,000
Number of shares repurchased during period (in shares) | shares			967,240			1,890,428
Value of stock repurchased during period			$ 21,000,000	$ 23,000,000		$ 44,000,000
Payment for repurchase of common stock (less than)			1,000,000			43,000,000	$ 0
Remaining shares authorized to be repurchased (in shares)			356,000,000			356,000,000
Stock-based compensation			$ 4,000,000	$ 1,000,000		$ 7,000,000
RSUs
Class of Stock [Line Items]
Shares granted (in shares) | shares						939,000
PSUs
Class of Stock [Line Items]
Shares granted (in shares) | shares						521,000
RSUs and PSUs
Class of Stock [Line Items]
Weighted average grant date fair value of shares (in dollars per share) | $ / shares						$ 24.40
Executive Officer | RSUs
Class of Stock [Line Items]
Shares granted (in shares) | shares						140,000
Board of Directors | RSUs
Class of Stock [Line Items]
Shares granted (in shares) | shares						63,000
Subsequent Event
Class of Stock [Line Items]
Payments of dividends		$ 8,000,000
Cash dividend per common share (in dollars per share) | $ / shares	$ 0.05