Schedule I Condensed Balance Sheets (Details) (Parenthetical) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Condensed Financial Statements, Captions [Line Items]
Common Stock, Shares Authorized	115	115
Common Stock, Shares, Issued	76	77
Common Stock, Shares, Outstanding	76	77
Preferred Stock, Value, Issued	$ 3,750	$ 0
Long-term income tax receivable	$ (658)	$ (530)
Preferred Stock, Shares Issued	4
Preferred Stock, Shares Outstanding	4
Common Stock, stated value per share	$ 0	$ 0
Parent Company [Member]
Condensed Financial Statements, Captions [Line Items]
Common Stock, Shares, Issued	76	77
Common Stock, Shares, Outstanding	76	77
Preferred Stock, Value, Issued	$ 3,750	$ 0
Long-term income tax receivable	$ (658)	$ (530)