Earnings Per Share - Schedule of Basic and Diluted Earnings Per Share (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended						9 Months Ended
	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Sep. 30, 2019	Sep. 30, 2018
Basic
Net income	$ 38	$ 66	$ 73	$ 929	$ 150	$ 58	$ 177	$ 1,137
Weighted average common shares outstanding – Basic	74,753,593			74,070,852			74,528,740	74,070,852
EPS – Basic	$ 0.51			$ 12.54			$ 2.37	$ 15.35
Diluted
Net income	$ 38	$ 66	$ 73	$ 929	$ 150	$ 58	$ 177	$ 1,137
Weighted average common shares outstanding – Basic	74,753,593			74,070,852			74,528,740	74,070,852
Dilutive effect of unvested RSUs and other contingently issuable shares	950,864						1,171,912
Weighted average common shares outstanding – Diluted	75,704,457			74,070,852			75,700,652	74,070,852
EPS – Diluted	$ 0.50			$ 12.54			$ 2.34	$ 15.35