Stockholders' (Deficit) Equity (Narrative) (Details) - USD ($) shares in Millions	1 Months Ended
	Feb. 11, 2021	Feb. 06, 2020	Dec. 31, 2020
Treasury Stock Repurchase Programs [Line Items]
Treasury Stock Shares Repurchased			240.3
Additional share repurchase amount authorized	$ 747,000,000.0	$ 743,000,000.0
Stock Repurchase Program, Authorized Amount	1,000,000,000.0	1,000,000,000.0
Remaining common stock available for repurchase	$ 253,000,000.0	$ 257,000,000.0
Payments for Repurchase of Common Stock			$ 10,980,000,000
Share Buyback Program [Member]
Treasury Stock Repurchase Programs [Line Items]
Remaining common stock available for repurchase			$ 335,600,000