Income taxes (Details) $ in Millions	Sep. 30, 2021 USD ($)
Income Tax Disclosure [Abstract]
Unrecognized tax benefits	$ 99
Unrecognized tax benefits that would impact effective tax rate if recognized	99
Accrued interest related to the gross unrecognized tax benefits excluded from the unrecognized tax benefits	18
Decrease in unrecognized tax benefits that is reasonably possible (up to)	$ 40

Amount of decrease reasonably possible in the next twelve months for the unrecognized tax benefit.

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Amount of unrecognized tax benefits.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
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Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
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Amount of interest expense accrued for an underpayment of income taxes.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 15
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The total amount of unrecognized tax benefits that, if recognized, would affect the effective tax rate.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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-Name Accounting Standards Codification
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