Subsequent events (Details) - Discontinued Operations, Disposed of by Sale - Alliance Healthcare - Subsequent Event $ in Billions	Jun. 01, 2021 USD ($)
Minimum
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Estimated fair value of proceeds from disposition	$ 6.8
Gain before currency translation adjustments	1.0
Net gain on disposal of discontinued operation	0.3
Maximum
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Estimated fair value of proceeds from disposition	6.9
Gain before currency translation adjustments	1.1
Net gain on disposal of discontinued operation	$ 0.4

Amount after tax of gain (loss) not previously recognized resulting from the disposal of a discontinued operation.

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-Name Accounting Standards Codification
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