Segment and Geographic Information - Schedule of Geographic Distributions of Revenues, Equity in Earnings of Affiliates, Adjusted Segment EBITDA, Depreciation and Amortization and Assets (Detail) - USD ($) $ in Millions		3 Months Ended
	Dec. 09, 2015	Mar. 31, 2016	Dec. 31, 2015	Mar. 31, 2015	Mar. 31, 2014	Dec. 31, 2012
Segment Reporting Information [Line Items]
Revenues		$ 10,260		$ 9,676
Equity in earnings of affiliates		12		19
Adjusted segment EBITDA		2,003		1,961
Depreciation and amortization		479		473
Interest expense		416		419
Losses (gains) on sales of facilities		1		(9)
Legal claim costs	$ 434	12	$ 120		$ 78	$ 175
Income before income taxes		1,095		1,078
National Group [Member]
Segment Reporting Information [Line Items]
Revenues		4,967		4,650
Equity in earnings of affiliates		(2)		(3)
Adjusted segment EBITDA		1,138		1,081
Depreciation and amortization		197		189
American Group [Member]
Segment Reporting Information [Line Items]
Revenues		4,780		4,501
Equity in earnings of affiliates		(9)		(8)
Adjusted segment EBITDA		983		949
Depreciation and amortization		218		221
Corporate and Other [Member]
Segment Reporting Information [Line Items]
Revenues		513		525
Equity in earnings of affiliates		(1)		(8)
Adjusted segment EBITDA		(118)		(69)
Depreciation and amortization		$ 64		$ 63