Consolidated Statements of Equity - USD ($) $ in Millions	Total	Common Stock Shares	Common Stock Amount	Accumulated Other Comprehensive Loss	Retained Earnings
Balance, shares at Dec. 31, 2016		88,946,704
Balance at Dec. 31, 2016	$ 2,344		$ 1,201	$ (7)	$ 1,150
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Shares issued pursuant to equity-based plans		167,561
Proceeds from issuance of shares pursuant to equity-based plans	2		2
Stock-based compensation	4		4	0	0
Dividends declared	(120)		0	0	(120)
Net income	187		0	0	187
Other comprehensive income (loss)	(1)		0	(1)	0
Balance, shares at Dec. 31, 2017		89,114,265
Balance at Dec. 31, 2017	2,416		1,207	(8)	1,217
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Shares issued pursuant to equity-based plans		153,694
Proceeds from issuance of shares pursuant to equity-based plans	1		1
Stock-based compensation	4		4	0	0
Dividends declared	(128)		0	0	(128)
Net income	212		0	0	212
Other comprehensive income (loss)	1		0	1	0
Balance, shares at Dec. 31, 2018		89,267,959
Balance at Dec. 31, 2018	2,506		1,212	(7)	1,301
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Shares issued pursuant to equity-based plans		119,165
Proceeds from issuance of shares pursuant to equity-based plans	1		1
Stock-based compensation	7		7	0	0
Dividends declared	(136)		0	0	(136)
Net income	214		0	0	214
Reclassification of stranded tax effects due to Tax Reform				(2)	(2)
Other comprehensive income (loss)	(1)		0	(1)	0
Balance, shares at Dec. 31, 2019		89,387,124
Balance at Dec. 31, 2019	$ 2,591		$ 1,220	$ (10)	$ 1,381