Goodwill And Intangible Assets, Net (Information Regarding Intangible Assets) (Details) - USD ($) $ in Millions	3 Months Ended
Jun. 30, 2015	Mar. 31, 2015
Intangible assets
Gross carrying amount	$ 5,317	$ 5,204
Accumulated amortization	(1,891)	(1,763)
Net carrying amount	$ 3,426	3,441
Customer lists
Intangible assets
Weighted average remaining amortization period (years)	9 years
Gross carrying amount	$ 2,717	2,683
Accumulated amortization	(1,190)	(1,116)
Net carrying amount	$ 1,527	1,567
Service agreements
Intangible assets
Weighted average remaining amortization period (years)	15 years
Gross carrying amount	$ 964	957
Accumulated amortization	(230)	(215)
Net carrying amount	$ 734	742
Pharmacy licenses
Intangible assets
Weighted average remaining amortization period (years)	26 years
Gross carrying amount	$ 926	874
Accumulated amortization	(83)	(65)
Net carrying amount	$ 843	809
Trademarks and trade names
Intangible assets
Weighted average remaining amortization period (years)	15 years
Gross carrying amount	$ 325	315
Accumulated amortization	(87)	(82)
Net carrying amount	$ 238	233
Technology-based intangible assets
Intangible assets
Weighted average remaining amortization period (years)	3 years
Gross carrying amount	$ 210	213
Accumulated amortization	(187)	(184)
Net carrying amount	$ 23	29
Other
Intangible assets
Weighted average remaining amortization period (years)	4 years
Gross carrying amount	$ 175	162
Accumulated amortization	(114)	(101)
Net carrying amount	$ 61	$ 61

Accumulated amount of amortization of assets, excluding financial assets and goodwill, lacking physical substance with a finite life.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 350

-SubTopic 30

-Section 50

-Paragraph 2

-Subparagraph (a)(1)

-URI http://asc.fasb.org/extlink&oid=26713463&loc=d3e16323-109275

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Amount before amortization of assets, excluding financial assets and goodwill, lacking physical substance with a finite life.

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