Details Of Intangible Assets Included In Other Long-Term Assets (Detail) (USD $) In Millions, unless otherwise specified	9 Months Ended
	Sep. 30, 2012	Dec. 31, 2011
Acquired Finite-Lived Intangible Assets [Line Items]
Weighted Average Life	11 years 2 months 12 days
Cost	$ 731	$ 648
Accumulated Amortization	266	213
Net	465	435
Customer contracts/relationships
Acquired Finite-Lived Intangible Assets [Line Items]
Weighted Average Life	10 years 3 months 18 days
Cost	484	429
Accumulated Amortization	215	182
Net	269	247
Trade names and technology
Acquired Finite-Lived Intangible Assets [Line Items]
Weighted Average Life	14 years 4 months 24 days
Cost	147	135
Accumulated Amortization	16	6
Net	131	129
Provider contracts
Acquired Finite-Lived Intangible Assets [Line Items]
Weighted Average Life	15 years 1 month 6 days
Cost	51	44
Accumulated Amortization	18	15
Net	33	29
Noncompetes And Other
Acquired Finite-Lived Intangible Assets [Line Items]
Weighted Average Life	6 years 10 months 24 days
Cost	49	40
Accumulated Amortization	17	10
Net	$ 32	$ 30