Basis of Presentation - Income Taxes and Noncontrolling Interest (Details) - USD ($) $ in Millions	3 Months Ended				9 Months Ended
	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Provision for/(benefit from) income taxes	$ 339.0		$ (329.0)	$ 409.0	$ 120.0	$ (31.0)
Effective tax rate (as a percent)			(23.10%)		1.70%	(0.40%)
Discrete tax benefits (charges)		$ 170.0	$ (99.0)
Other (income) and expense
Noncontrolling interest amounts, net of tax	$ 4.4			$ 3.1	$ 11.5	$ 7.5
Accounting Standards Update 2016-16, Intra-Entity Transfers of Assets Other Than Inventory | Early adoption
Provision for/(benefit from) income taxes			$ (582.0)		$ (582.0)