Consolidated Statements of Comprehensive Income - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Net income	$ 410	$ 179	$ 211
Other comprehensive (loss) income :
Adjustment to pension liability	(10)	(7)	1
Income tax benefit	(2)	(2)	0
Adoption of ASU 2018-02		0
Other comprehensive (loss) income	(8)	(10)	1
Comprehensive income	402	169	212
AOCI Attributable to Parent [Member]
Net income	0	0	0
Other comprehensive (loss) income :
Adoption of ASU 2018-02	$ 0	$ (5)	$ 0