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Amount after accumulated impairment loss of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

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Amount of divestiture of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

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Amount of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations.

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Goodwill (Details) - USD ($) $ in Millions	3 Months Ended
Goodwill (Details) - USD ($) $ in Millions	Mar. 31, 2018	Mar. 31, 2017	Jan. 02, 2018
Goodwill
Income tax provision	$ 472	$ 572
Goodwill
Goodwill, beginning balance	38,451
Acquisitions	62
Sale of RxCrossroads reporting unit	(398)
Goodwill, ending balance	38,115
Pharmacy Services Segment
Goodwill
Goodwill, beginning balance	21,819
Acquisitions	26
Goodwill, ending balance	21,845
Retail/LTC Segment
Goodwill
Goodwill, impairment loss	199
Goodwill
Goodwill, beginning balance	16,632
Acquisitions	36
Sale of RxCrossroads reporting unit	(398)
Goodwill, ending balance	$ 16,270
Rx Crossroads Member
Disposal group
Consideration			$ 725