Guarantor Financial Information - Condensed Consolidated Balance Sheet (Unaudited) (Detail) - USD ($) $ in Millions	Mar. 31, 2019	Jan. 01, 2019	Dec. 31, 2018	Mar. 31, 2018	Dec. 31, 2017
Current assets
Cash and cash equivalents	$ 402		$ 524	$ 462	$ 656
Trade and other receivables, net	1,221		1,118
Prepaid expenses and other current assets	424		361
Total current assets	2,047		2,003
Non-current assets
Property, plant and equipment, net	473		468
Operating lease right-of-use asset	506	$ 500
Goodwill	7,009		6,987
Other intangible assets, net	5,020		5,024
Deferred tax assets	334		333
Other non-current assets	353		364
Total assets	15,742		15,179
Current liabilities
Accounts payable and other current liabilities	1,071		1,119
Deferred revenues	376		355
Income tax liabilities	85		76
Current portion of long-term debt, finance/capital lease obligations and short-term borrowings	385		107
Total current liabilities	1,917		1,657
Non-current liabilities
Long-term debt and finance/capital lease obligations	8,242		8,280
Deferred tax liabilities	1,100		1,108
Operating lease liabilities	468
Other non-current liabilities	1,026		1,091
Total liabilities	12,753		12,136
Total shareholders’ equity	2,790		2,847
Noncontrolling interests	199		196
Total equity	2,989		3,043	4,458	4,443
Total liabilities and equity	15,742		15,179
Parent
Current assets
Cash and cash equivalents	3		3	1	2
Prepaid expenses and other current assets	1
Intercompany receivables	3		3
Total current assets	7		6
Non-current assets
Deferred tax assets	1		1
Equity investment in subsidiaries	2,757		2,815
Intercompany loans	25		25
Total assets	2,790		2,847
Non-current liabilities
Total shareholders’ equity	2,790		2,847
Total equity	2,790		2,847
Total liabilities and equity	2,790		2,847
Issuers
Current assets
Cash and cash equivalents	2			1	1
Trade and other receivables, net	1		1
Prepaid expenses and other current assets	1		3
Intercompany receivables	1,442		1,310
Total current assets	1,446		1,314
Non-current assets
Other non-current assets	12		19
Equity investment in subsidiaries	1,225		1,232
Intercompany loans	8,822		8,822
Total assets	11,505		11,387
Current liabilities
Accounts payable and other current liabilities	103		62
Current portion of long-term debt, finance/capital lease obligations and short-term borrowings	55		54
Total current liabilities	158		116
Non-current liabilities
Long-term debt and finance/capital lease obligations	8,144		8,170
Deferred tax liabilities	71		71
Other non-current liabilities	6		3
Total liabilities	8,379		8,360
Total shareholders’ equity	3,126		3,027
Total equity	3,126		3,027
Total liabilities and equity	11,505		11,387
Guarantor
Current assets
Cash and cash equivalents	60		79	16	69
Trade and other receivables, net	460		377
Prepaid expenses and other current assets	290		234
Intercompany receivables	353		399
Total current assets	1,163		1,089
Non-current assets
Property, plant and equipment, net	292		303
Operating lease right-of-use asset	221
Goodwill	5,543		5,531
Other intangible assets, net	4,504		4,545
Other non-current assets	270		273
Equity investment in subsidiaries	3,399		1,936
Intercompany loans	897		2,220
Total assets	16,289		15,897
Current liabilities
Accounts payable and other current liabilities	440		541
Deferred revenues	230		225
Income tax liabilities	16		20
Current portion of long-term debt, finance/capital lease obligations and short-term borrowings	316		46
Intercompany payables	1,513		1,408
Total current liabilities	2,515		2,240
Non-current liabilities
Long-term debt and finance/capital lease obligations	82		95
Deferred tax liabilities	953		956
Operating lease liabilities	245
Intercompany loans	8,951		8,952
Other non-current liabilities	786		839
Total liabilities	13,532		13,082
Total shareholders’ equity	2,757		2,815
Total equity	2,757		2,815
Total liabilities and equity	16,289		15,897
Non-Guarantor
Current assets
Cash and cash equivalents	337		442	$ 444	$ 584
Trade and other receivables, net	760		740
Prepaid expenses and other current assets	132		124
Intercompany receivables	68		94
Total current assets	1,297		1,400
Non-current assets
Property, plant and equipment, net	181		165
Operating lease right-of-use asset	285
Goodwill	1,466		1,456
Other intangible assets, net	516		479
Deferred tax assets	333		332
Other non-current assets	71		72
Intercompany loans	104		105
Total assets	4,253		4,009
Current liabilities
Accounts payable and other current liabilities	528		516
Deferred revenues	146		130
Income tax liabilities	69		56
Current portion of long-term debt, finance/capital lease obligations and short-term borrowings	14		7
Intercompany payables	353		398
Total current liabilities	1,110		1,107
Non-current liabilities
Long-term debt and finance/capital lease obligations	16		15
Deferred tax liabilities	76		81
Operating lease liabilities	223
Intercompany loans	897		2,220
Other non-current liabilities	234		249
Total liabilities	2,556		3,672
Total shareholders’ equity	1,498		141
Noncontrolling interests	199		196
Total equity	1,697		337
Total liabilities and equity	4,253		4,009
Consolidation Eliminations
Current assets
Intercompany receivables	(1,866)		(1,806)
Total current assets	(1,866)		(1,806)
Non-current assets
Equity investment in subsidiaries	(7,381)		(5,983)
Intercompany loans	(9,848)		(11,172)
Total assets	(19,095)		(18,961)
Current liabilities
Intercompany payables	(1,866)		(1,806)
Total current liabilities	(1,866)		(1,806)
Non-current liabilities
Intercompany loans	(9,848)		(11,172)
Total liabilities	(11,714)		(12,978)
Total shareholders’ equity	(7,381)		(5,983)
Total equity	(7,381)		(5,983)
Total liabilities and equity	$ (19,095)		$ (18,961)