Leases (Supplemental Balance Sheet Information) (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Leases [Abstract]
Operating lease ROU assets, other long term assets	$ 763.7
Operating lease liabilities, accrued expenses and other liabilities	157.8	$ 0.0
Operating lease liabilities, other long-term liabilities	639.1	$ 0.0
Total operating lease liabilities	$ 796.9
Weighted average remaining lease term	7 years
Weighted average discount rate	3.10%