Condensed Consolidated Balance Sheets (Unaudited) (Parenthetical) - USD ($) $ in Millions	Mar. 31, 2021	Dec. 31, 2020
Allowance for credit losses:
Accounts Receivable, Allowance for Credit Loss, Current	$ (39)	$ (51)
Convertible Preferred Stock:
Temporary Equity, Par or Stated Value Per Share	$ 0.01	$ 0.01
Temporary Equity, Shares Authorized	3,000,000.0	3,000,000.0
Temporary Equity, Shares Issued	300,000	300,000
Temporary Equity, Shares Outstanding	300,000	300,000
Temporary Equity, Aggregate Amount of Redemption Requirement	$ 276	$ 276
Temporary Equity, Liquidation Preference	$ 276	$ 276
Stockholders' Equity:
Preferred Stock, Par or Stated Value Per Share	$ 0.01	$ 0.01
Preferred Stock, Shares Authorized	100,000,000.0	100,000,000.0
Preferred Stock, Shares Issued	0	0
Preferred Stock, Shares Outstanding	0	0
Common Stock, Par or Stated Value Per Share	$ 0.01	$ 0.01
Common Stock, Shares Authorized	500,000,000.0	500,000,000.0
Common Stock, Shares, Issued	130,600,000	129,100,000
Common Stock, Shares, Outstanding	130,600,000	129,100,000