Interim Financial Statements - Recent Accounting Pronouncements - Leases (Details) - USD ($) $ in Millions	Mar. 31, 2019	Jan. 01, 2019	Dec. 31, 2018
Assets
Operating lease right-of-use assets	$ 2,416.4	$ 2,425.6
Liabilities and Equity
Accrued expenses and other current liabilities	704.7	636.8	$ 566.6
Long-term operating lease liabilities	2,378.2	2,387.5
Deferred tax liabilities	591.4	578.7	577.8
Other long-term liabilities	450.0	481.0	519.0
Retained earnings	$ 2,438.8	2,370.8	$ 2,365.8
ASC 842 | Impact of Adoption
Assets
Operating lease right-of-use assets		2,425.6
Liabilities and Equity
Accrued expenses and other current liabilities		70.2
Long-term operating lease liabilities		2,387.5
Deferred tax liabilities		0.9
Other long-term liabilities		(38.0)
Retained earnings		$ 5.0