Subsidiary Guarantors of Long-Term Debt - Condensed Consolidating Balance Sheet (Detail) (USD $) In Millions, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014	Mar. 31, 2014	Dec. 31, 2013
Assets
Cash and cash equivalents	$ 296	$ 294	$ 307	$ 400
Trade accounts receivable, net	765	798
Prepaid expenses and other current assets	437	394
Total current assets	1,498	1,486
Intangible assets, net	1,974	2,003
Goodwill	5,204	5,209
Other long-term assets	659	639
Total assets	9,335	9,337
Liabilities and Shareholders' Equity
Accounts payable and accrued expenses	936	905
Current maturities of long-term debt	95	92
Deferred revenue	470	489
Total current liabilities	1,501	1,486
Long-term debt	3,757	3,711
Other long-term liabilities	859	845
Total liabilities	6,117	6,042
Total shareholders' equity	3,218	3,295
Total liabilities and shareholders' equity	9,335	9,337
Parent Company [Member]
Assets
Cash and cash equivalents	25	21	30	139
Prepaid expenses and other current assets	47	48
Total current assets	72	69
Investments in consolidated affiliates	11,157	10,987
Intangible assets, net	22	23
Other long-term assets	34	36
Total assets	11,285	11,115
Liabilities and Shareholders' Equity
Accounts payable and accrued expenses	175	119
Current maturities of long-term debt	90	90
Total current liabilities	265	209
Long-term debt	3,750	3,707
Due to consolidated affiliates	3,282	3,137
Other long-term liabilities	770	767
Total liabilities	8,067	7,820
Total shareholders' equity	3,218	3,295
Total liabilities and shareholders' equity	11,285	11,115
Guarantor Subsidiaries [Member]
Assets
Cash and cash equivalents	71	80	91	76
Trade accounts receivable, net	503	510
Prepaid expenses and other current assets	232	209
Total current assets	806	799
Due from consolidated affiliates	2,559	2,467
Intangible assets, net	1,715	1,734
Goodwill	4,154	4,154
Other long-term assets	522	496
Total assets	9,756	9,650
Liabilities and Shareholders' Equity
Accounts payable and accrued expenses	571	586
Current maturities of long-term debt	5	2
Deferred revenue	273	285
Total current liabilities	849	873
Long-term debt	7	4
Other long-term liabilities	43	31
Total liabilities	899	908
Total shareholders' equity	8,857	8,742
Total liabilities and shareholders' equity	9,756	9,650
Non-Guarantor Subsidiaries [Member]
Assets
Cash and cash equivalents	200	193	186	185
Trade accounts receivable, net	262	288
Prepaid expenses and other current assets	158	137
Total current assets	620	618
Due from consolidated affiliates	723	670
Intangible assets, net	237	246
Goodwill	1,050	1,055
Other long-term assets	103	107
Total assets	2,733	2,696
Liabilities and Shareholders' Equity
Accounts payable and accrued expenses	190	200
Deferred revenue	197	204
Total current liabilities	387	404
Other long-term liabilities	46	47
Total liabilities	433	451
Total shareholders' equity	2,300	2,245
Total liabilities and shareholders' equity	2,733	2,696
Eliminations [Member]
Assets
Due from consolidated affiliates	(3,282)	(3,137)
Investments in consolidated affiliates	(11,157)	(10,987)
Total assets	(14,439)	(14,124)
Liabilities and Shareholders' Equity
Due to consolidated affiliates	(3,282)	(3,137)
Total liabilities	(3,282)	(3,137)
Total shareholders' equity	(11,157)	(10,987)
Total liabilities and shareholders' equity	$ (14,439)	$ (14,124)