Segment information - Additions to property, plant and equipment and intangible assets for each of the segments (Details) - USD ($) $ in Millions	3 Months Ended
Jun. 30, 2025	Jun. 30, 2024
Segment Reporting Information [Line Items]
Total property, plant and equipment and intangible asset additions	$ 1,390	$ 1,186
Americas Materials Solutions
Segment Reporting Information [Line Items]
Total property, plant and equipment and intangible asset additions	582	568
Americas Building Solutions
Segment Reporting Information [Line Items]
Total property, plant and equipment and intangible asset additions	314	233
International Solutions
Segment Reporting Information [Line Items]
Total property, plant and equipment and intangible asset additions	$ 494	$ 385

Amount of expenditure for addition to long-lived assets included in determination of segment assets by chief operating decision maker (CODM) or otherwise regularly provided to CODM. Excludes expenditure for addition to financial instrument, long-term customer relationship of financial institution, mortgage and other servicing rights, deferred policy acquisition cost, and deferred tax assets.

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 55
-Paragraph 48
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482785/280-10-55-48

Reference 2: http://www.xbrl.org/2003/role/exampleRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 55
-Paragraph 49
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482785/280-10-55-49

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 270
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (i)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482964/270-10-50-1

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 32
-Subparagraph (ee)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482810/280-10-50-32

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 25
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482810/280-10-50-25

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration