Financing - Commercial Paper Programs (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Debt Instrument [Line Items]
Carrying Value	$ 6,328.4	$ 3,430.3
Commercial Paper
Debt Instrument [Line Items]
Carrying Value	1,100.0
Commercial Paper | U.S. dollar-denominated
Debt Instrument [Line Items]
Carrying Value	$ 884.4	390.1
Annual effective rate (as a percent)	2.14%
Weighted average remaining maturity (in days)	13 days
Commercial Paper | Euro-denominated
Debt Instrument [Line Items]
Carrying Value	$ 264.1	$ 270.1
Annual effective rate (as a percent)	(0.10%)
Weighted average remaining maturity (in days)	33 days