Financial Information for Guarantor Subsidiaries and Non-Guarantor Subsidiaries - Supplemental Condensed Consolidating Balance Sheet (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Assets
Cash and cash equivalents	$ 788.8	$ 115.1
Restricted cash	29.0	24.7
Accounts receivable, net	540.9	495.0
Notes receivable, net	143.5	125.4
Inventories	243.1	242.3
Prepaid expenses, deposits and other current assets	131.1	114.1
Property and equipment, net	568.2	612.2
Investment in subsidiaries	0.0	0.0
Goodwill	2,956.1	2,888.4	$ 3,013.7
Intangible assets, net	1,604.6	1,768.3
Intercompany balances	0.0	0.0
Software, net	339.4	409.1
Other assets	380.6	292.8
Total assets	7,725.3	7,087.4	7,732.2
Liabilities and stockholders’ (deficit) equity
Current portion of long-term debt	40.3	49.3
Other current liabilities	699.5	643.1
Long-term debt, excluding current portion	8,736.3	8,024.9
Other long-term liabilities	276.2	305.8
Intercompany balances	0.0	0.0
Stockholders’ (deficit) equity	(2,027.0)	(1,935.7)	$ (1,495.5)
Total liabilities and stockholders' deficit	7,725.3	7,087.4
Non-current restricted cash	16.3	17.1
Reportable Legal Entities | Parent Company
Assets
Cash and cash equivalents	732.6	32.7
Restricted cash	0.0	0.0
Accounts receivable, net	0.4	0.0
Notes receivable, net	0.0	0.0
Inventories	0.0	0.0
Prepaid expenses, deposits and other current assets	6.5	11.6
Property and equipment, net	28.8	5.6
Investment in subsidiaries	3,098.7	3,000.7
Goodwill	0.0	0.0
Intangible assets, net	15.7	185.8
Intercompany balances	0.0	0.0
Software, net	67.2	74.7
Other assets	234.4	233.6
Total assets	4,184.3	3,544.7
Liabilities and stockholders’ (deficit) equity
Current portion of long-term debt	0.0	0.0
Other current liabilities	67.6	100.5
Long-term debt, excluding current portion	0.0	248.7
Other long-term liabilities	68.8	159.0
Intercompany balances	6,074.9	4,972.2
Stockholders’ (deficit) equity	(2,027.0)	(1,935.7)
Total liabilities and stockholders' deficit	4,184.3	3,544.7
Reportable Legal Entities | Guarantor Subsidiaries
Assets
Cash and cash equivalents	0.0	0.0
Restricted cash	28.3	24.6
Accounts receivable, net	192.6	199.2
Notes receivable, net	121.1	94.4
Inventories	91.8	83.1
Prepaid expenses, deposits and other current assets	41.6	45.6
Property and equipment, net	295.6	369.3
Investment in subsidiaries	987.7	944.0
Goodwill	1,880.4	1,931.6
Intangible assets, net	1,335.3	1,343.0
Intercompany balances	0.0	0.0
Software, net	199.0	264.6
Other assets	62.0	50.8
Total assets	5,235.4	5,350.2
Liabilities and stockholders’ (deficit) equity
Current portion of long-term debt	0.0	0.0
Other current liabilities	254.2	216.3
Long-term debt, excluding current portion	0.0	0.0
Other long-term liabilities	650.3	468.8
Intercompany balances	37.4	559.5
Stockholders’ (deficit) equity	4,293.5	4,105.6
Total liabilities and stockholders' deficit	5,235.4	5,350.2
Non-current restricted cash	15.6	16.4
Reportable Legal Entities | Non-Guarantor Subsidiaries
Assets
Cash and cash equivalents	59.4	81.8
Restricted cash	0.1	0.1
Accounts receivable, net	279.8	234.4
Notes receivable, net	22.4	31.0
Inventories	131.8	138.1
Prepaid expenses, deposits and other current assets	52.7	41.2
Property and equipment, net	179.9	154.9
Investment in subsidiaries	0.0	0.0
Goodwill	835.4	768.5
Intangible assets, net	218.7	202.0
Intercompany balances	222.5	116.6
Software, net	48.5	48.4
Other assets	270.3	173.5
Total assets	2,321.5	1,990.5
Liabilities and stockholders’ (deficit) equity
Current portion of long-term debt	7.5	6.3
Other current liabilities	206.4	168.7
Long-term debt, excluding current portion	3.3	8.9
Other long-term liabilities	110.9	67.2
Intercompany balances	0.0	0.0
Stockholders’ (deficit) equity	1,993.4	1,739.4
Total liabilities and stockholders' deficit	2,321.5	1,990.5
Non-current restricted cash	0.7	0.7
Reportable Legal Entities | SGI
Assets
Cash and cash equivalents	0.0	1.7
Restricted cash	0.6	0.0
Accounts receivable, net	68.1	61.4
Notes receivable, net	0.0	0.0
Inventories	40.7	40.3
Prepaid expenses, deposits and other current assets	30.3	15.7
Property and equipment, net	91.5	98.4
Investment in subsidiaries	867.9	926.7
Goodwill	240.3	188.3
Intangible assets, net	34.9	37.5
Intercompany balances	5,889.8	5,415.1
Software, net	24.7	21.4
Other assets	388.8	236.5
Total assets	7,677.6	7,043.0
Liabilities and stockholders’ (deficit) equity
Current portion of long-term debt	32.8	43.0
Other current liabilities	199.0	158.7
Long-term debt, excluding current portion	8,733.0	7,767.3
Other long-term liabilities	11.3	12.4
Intercompany balances	0.0	0.0
Stockholders’ (deficit) equity	(1,298.5)	(938.4)
Total liabilities and stockholders' deficit	7,677.6	7,043.0
Eliminating Entries
Assets
Cash and cash equivalents	(3.2)	(1.1)
Restricted cash	0.0	0.0
Accounts receivable, net	0.0	0.0
Notes receivable, net	0.0	0.0
Inventories	(21.2)	(19.2)
Prepaid expenses, deposits and other current assets	0.0	0.0
Property and equipment, net	(27.6)	(16.0)
Investment in subsidiaries	(4,954.3)	(4,871.4)
Goodwill	0.0	0.0
Intangible assets, net	0.0	0.0
Intercompany balances	(6,112.3)	(5,531.7)
Software, net	0.0	0.0
Other assets	(574.9)	(401.6)
Total assets	(11,693.5)	(10,841.0)
Liabilities and stockholders’ (deficit) equity
Current portion of long-term debt	0.0	0.0
Other current liabilities	(27.7)	(1.1)
Long-term debt, excluding current portion	0.0	0.0
Other long-term liabilities	(565.1)	(401.6)
Intercompany balances	(6,112.3)	(5,531.7)
Stockholders’ (deficit) equity	(4,988.4)	(4,906.6)
Total liabilities and stockholders' deficit	$ (11,693.5)	$ (10,841.0)