Quarterly Financial Data (Unaudited) (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Quarterly Financial Information Disclosure [Abstract]
Revenue	$ 1,373	$ 1,220	$ 1,160	$ 1,123	$ 1,371	$ 1,296	$ 1,345	$ 1,237	$ 4,876	$ 5,249	$ 5,207
Gross Profit	526	461	434	409	537	509	526	474	1,830	2,046	2,026
Operating income	179	73	54	61	195	11	171	109	367	486	654
Net income	$ 148	$ 37	$ 31	$ 38	$ 118	$ 65	$ 139	$ 79	$ 254	$ 401	$ 549
Basic (in dollars per share)	$ 0.82	$ 0.20	$ 0.17	$ 0.21	$ 0.66	$ 0.36	$ 0.77	$ 0.44	$ 1.41	$ 2.23	$ 3.05
Diluted (in dollars per share)	$ 0.82	$ 0.20	$ 0.17	$ 0.21	$ 0.65	$ 0.36	$ 0.77	$ 0.43	$ 1.40	$ 2.21	$ 3.03
Goodwill, Impairment Loss		$ 58				$ 148			$ 58	$ 148	$ 0