Stockholders' (Deficit) Equity (Narrative) (Details) - USD ($) $ in Millions	1 Months Ended
	Feb. 09, 2017	Feb. 11, 2016	Dec. 31, 2016
Treasury Stock Repurchase Programs [Line Items]
Treasury Stock Shares Repurchased			221,000,000
Additional share repurchase amount authorized	$ 640.9	$ 611.2
Common stock authorized to repurchase	1,000.0	1,000.0
Remaining common stock available for repurchase	$ 359.1	$ 388.8
Payments for Repurchase of Common Stock			$ 8,200.0
Share Buyback Program [Member]
Treasury Stock Repurchase Programs [Line Items]
Remaining common stock available for repurchase			$ 429.2