Shareholders' Equity - Schedule of Common Stock (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended									9 Months Ended
	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Sep. 30, 2021	Sep. 30, 2020
Equity, Class of Treasury Stock [Line Items]
Cash dividends declared (in USD per share)	$ 0.57	$ 0.52	$ 0.52		$ 0.52	$ 0.52	$ 0.52			$ 1.61	$ 1.56
Total (In millions)	$ 209	$ 179	$ 182		$ 184	$ 183	$ 183			$ 570	$ 550
2019 Program
Equity, Class of Treasury Stock [Line Items]
Shares Acquired (in shares)	0.0				0.0					11.2	6.5
Average Cost per Share (USD per share)	$ 0				$ 0					$ 80.00	$ 77.35
Total Acquired	$ 0			$ 0	$ 0	$ 0	$ 500	$ 500	$ 500	$ 900	$ 500