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Held for Sale - Narrative (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended	12 Months Ended
Held for Sale - Narrative (Details) - USD ($) $ in Millions	Sep. 30, 2020	Sep. 30, 2020	Mar. 31, 2020	Dec. 31, 2020	Jun. 30, 2019
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Assets held for sale	$ 833	$ 833	$ 906
Liabilities held for sale	537	537	683
Joint Venture
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Ownership interest (percent)					70.00%
Joint Venture \| Subsequent Event
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Ownership interest (percent)				30.00%
Held-for-sale
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Assets held for sale	833	833
Liabilities held for sale	537	537
Held-for-sale \| German Pharmaceutical Wholesale Joint Venture
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Impairment	$ 10	10
Favorable (unfavorable) cumulative foreign currency translation adjustment		$ (11)	$ 3