Leases - Balance Sheet Location of Assets and Liabilities (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019	Jan. 01, 2019
Lessee, Lease, Description [Line Items]
Operating lease assets	$ 186.0	$ 129.9	$ 164.0
Finance leases	31.0	27.6
Right-of-use assets	217.0	157.5
Present value of lease liabilities	221.3	158.2
Total operating lease liabilities	193.3	133.7
Present value of lease liabilities	$ 28.0	$ 24.5
Finance Lease, Right-of-Use Asset, Statement of Financial Position [Extensible List]	us-gaap:OtherAssets	us-gaap:OtherAssets
Operating Lease, Liability, Current, Statement of Financial Position [Extensible List]	us-gaap:OtherLiabilitiesCurrent	us-gaap:OtherLiabilitiesCurrent
Finance Lease, Liability, Current, Statement of Financial Position [Extensible List]	us-gaap:DebtCurrent	us-gaap:DebtCurrent
Operating Lease, Liability, Noncurrent, Statement of Financial Position [Extensible List]	us-gaap:OtherLiabilitiesNoncurrent	us-gaap:OtherLiabilitiesNoncurrent
Finance Lease, Liability, Noncurrent, Statement of Financial Position [Extensible List]	us-gaap:LongTermDebtNoncurrent	us-gaap:LongTermDebtNoncurrent
Operating lease assets
Lessee, Lease, Description [Line Items]
Operating lease assets	$ 186.0	$ 129.9
Other non-current assets
Lessee, Lease, Description [Line Items]
Finance leases	31.0	27.6
Other accrued liabilities
Lessee, Lease, Description [Line Items]
Operating lease liability, current	34.0	32.0
Current indebtedness
Lessee, Lease, Description [Line Items]
Finance lease liability, current	7.2	3.4
Other non-current liabilities
Lessee, Lease, Description [Line Items]
Operating lease liability, noncurrent	159.3	101.7
Long-term debt, less current portion
Lessee, Lease, Description [Line Items]
Finance lease liability, noncurrent	20.8	21.1
CSCA
Lessee, Lease, Description [Line Items]
Operating lease assets	22.8	22.4
Finance leases	16.7	16.8
Total operating lease liabilities	23.2	22.8
Present value of lease liabilities	17.0	16.6
CSCI
Lessee, Lease, Description [Line Items]
Operating lease assets	34.4	41.6
Finance leases	5.9	5.8
Total operating lease liabilities	35.2	42.4
Present value of lease liabilities	2.5	2.9
RX
Lessee, Lease, Description [Line Items]
Operating lease assets	84.4	35.1
Finance leases	1.2	0.8
Total operating lease liabilities	85.1	36.3
Present value of lease liabilities	1.1	0.8
Unallocated
Lessee, Lease, Description [Line Items]
Operating lease assets	44.4	30.8
Finance leases	7.2	4.2
Total operating lease liabilities	49.8	32.2
Present value of lease liabilities	$ 7.4	$ 4.2