Acquisitions & Divestitures Other Divestitures (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Divestitures [Line Items]
Proceeds from disposition of assets	$ 617.4	$ 33.3
Net gain (loss) from asset sales, inclusive of restructuring costs	(13.2)	3.5
Non-core properties Divestitures [Member]
Divestitures [Line Items]
Proceeds from disposition of assets	2.1	33.3
Net gain (loss) from asset sales, inclusive of restructuring costs	$ (0.4)	$ 2.5