Revenue (Disaggregation of Revenue by Geographical Area) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Disaggregation of Revenue [Line Items]
Revenue	$ 5,636.7	$ 5,585.0	$ 10,728.9	$ 10,548.8
U.S.
Disaggregation of Revenue [Line Items]
Revenue	3,252.5	3,242.3	6,143.3	6,037.9
Europe
Disaggregation of Revenue [Line Items]
Revenue	928.2	941.0	1,828.5	1,834.8
Japan
Disaggregation of Revenue [Line Items]
Revenue	653.2	640.4	1,196.9	1,177.2
Other foreign countries
Disaggregation of Revenue [Line Items]
Revenue	$ 802.8	$ 761.2	$ 1,560.2	$ 1,498.8