Details Of Intangible Assets Included In Other Long-Term Assets (Detail) (USD $) In Millions, unless otherwise specified	6 Months Ended
	Jun. 30, 2012 Year	Dec. 31, 2011
Acquired Finite-Lived Intangible Assets [Line Items]
Weighted Average Life, years	11.6
Cost	$ 687	$ 648
Accumulated Amortization	247	213
Net	440	435
Customer contracts/relationships
Acquired Finite-Lived Intangible Assets [Line Items]
Weighted Average Life, years	10.5
Cost	459	429
Accumulated Amortization	204	182
Net	255	247
Trade names and technology
Acquired Finite-Lived Intangible Assets [Line Items]
Weighted Average Life, years	15.0
Cost	136	135
Accumulated Amortization	12	6
Net	124	129
Provider contracts
Acquired Finite-Lived Intangible Assets [Line Items]
Weighted Average Life, years	15.1
Cost	51	44
Accumulated Amortization	17	15
Net	34	29
Noncompetes and Other
Acquired Finite-Lived Intangible Assets [Line Items]
Weighted Average Life, years	7.1
Cost	41	40
Accumulated Amortization	14	10
Net	$ 27	$ 30