Goodwill (Details) $ in Millions	9 Months Ended
	Sep. 30, 2018 USD ($)
Goodwill activity:
Balance at beginning of year	$ 8,405.5
Business acquisition and disposition	9.8
Goodwill, Purchase Accounting Adjustments	(2.9)
Foreign currency translation	(79.4)
Balance at end of year	8,333.0
UNITED STATES
Goodwill activity:
Balance at beginning of year	5,928.5
Business acquisition and disposition	0.0
Goodwill, Purchase Accounting Adjustments	0.0
Foreign currency translation	0.0
Balance at end of year	5,928.5
Canada [Member]
Goodwill activity:
Balance at beginning of year	932.1
Business acquisition and disposition	0.0
Goodwill, Purchase Accounting Adjustments	(2.9)
Foreign currency translation	(24.3)
Balance at end of year	904.9
Europe [Member]
Goodwill activity:
Balance at beginning of year	1,538.0
Business acquisition and disposition	9.8
Goodwill, Purchase Accounting Adjustments	0.0
Foreign currency translation	(54.3)
Balance at end of year	1,493.5
International [Member]
Goodwill activity:
Balance at beginning of year	6.9
Business acquisition and disposition	0.0
Goodwill, Purchase Accounting Adjustments	0.0
Foreign currency translation	(0.8)
Balance at end of year	$ 6.1