Stockholders' Equity (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Mar. 31, 2021	Dec. 31, 2018
Purchases of common stock, shares	400,000	500,000	400,000
Purchases of common stock, value	$ 70	$ 76	$ 44
At the Market Stock Offering Program, aggregate value of common stock	$ 750				$ 750
Availability Under ATM				$ 750
Conversion factor, 6.785% Mandatory Convertible Preferred Stock		8.8043
Common Stock [Member] | Conversion of 6.875% Mandatory Convertible Preferred Stock [Domain]
Conversion of Stock, Shares Issued		14,000,000
6.875% Mandatory Convertible Preferred Stock [Member] | Conversion of 6.875% Mandatory Convertible Preferred Stock [Domain]
Conversion of Stock, Shares Converted		2,000,000