Details of Intangible Assets Included in Other Long-Term Assets (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Dec. 31, 2013
Acquired Finite-Lived Intangible Assets [Line Items]
Weighted Average Life	10 years 4 months 24 days
Cost	$ 1,057	$ 1,095
Accumulated Amortization	400	402
Net	657	693
Customer contracts/relationships
Acquired Finite-Lived Intangible Assets [Line Items]
Weighted Average Life	9 years 9 months 18 days
Cost	764	792
Accumulated Amortization	310	310
Net	454	482
Trade names and technology
Acquired Finite-Lived Intangible Assets [Line Items]
Weighted Average Life	13 years 2 months 12 days
Cost	198	200
Accumulated Amortization	43	40
Net	155	160
Provider contracts
Acquired Finite-Lived Intangible Assets [Line Items]
Weighted Average Life	16 years 6 months
Cost	45	51
Accumulated Amortization	18	23
Net	27	28
Noncompetes And Other
Acquired Finite-Lived Intangible Assets [Line Items]
Weighted Average Life	6 years 6 months
Cost	50	52
Accumulated Amortization	29	29
Net	$ 21	$ 23