Presentation of Financial Statements (Details) - USD ($) $ in Millions	Jun. 30, 2019	Jan. 01, 2019	Dec. 31, 2018	Dec. 31, 2017
Accounting Changes [Line Items]
Operating leases, liability	$ 1,597.0
Other current assets	1,290.9	$ 1,212.2	$ 1,241.4
Operating Lease Right-Of-Use Assets	1,435.3	1,306.5	0.0
Total assets	25,042.1	25,894.3	24,617.0
Other current liabilities	1,896.7	2,131.1	1,958.6
Long-Term Liability - Operating Leases	1,317.9	1,258.5	0.0
Long-Term Liabilities	975.1	1,044.1	1,197.8
Total liabilities and equity	$ 25,042.1	25,894.3	24,617.0
Cumulative effect of accounting change			0.0	$ 24.0
Adoption of ASC 842 Increase (Decrease)
Accounting Changes [Line Items]
Operating leases, liability		1,490.1
Other current assets		(29.2)
Operating Lease Right-Of-Use Assets		1,306.5
Total assets		1,277.3
Other current liabilities		172.5
Long-Term Liability - Operating Leases		1,258.5
Long-Term Liabilities		(153.7)
Total liabilities and equity		$ 1,277.3
Retained Earnings
Accounting Changes [Line Items]
Cumulative effect of accounting change			$ 22.3	$ 23.6