Stockholders' (Deficit) Equity (Narrative) (Details) - USD ($) $ in Millions	1 Months Ended
	Feb. 06, 2020	Feb. 07, 2019	Dec. 31, 2019
Treasury Stock Repurchase Programs [Line Items]
Treasury Stock Shares Repurchased			236,400,000
Additional share repurchase amount authorized	$ 743.0	$ 602.9
Stock Repurchase Program, Authorized Amount	1,000.0	1,000.0
Remaining common stock available for repurchase	$ 257.0	$ 397.1
Payments for Repurchase of Common Stock			$ 10,200.0
Share Buyback Program [Member]
Treasury Stock Repurchase Programs [Line Items]
Remaining common stock available for repurchase			$ 327.5