XML 134 R93.htm IDEA: XBRL DOCUMENT v3.21.1

Dividends - Summary of Dividends Paid (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Mar. 31, 2019
Dividends Payable [Line Items]
Dividends	$ 0.0	$ 158.6	$ 172.1
FY 2021 special dividend
Dividends Payable [Line Items]
Interim ordinary dividend to shareholders (in dollars per share)	$ 0.70
Dividends	$ 309.6
FY 2020 first half dividend
Dividends Payable [Line Items]
Interim ordinary dividend to shareholders (in dollars per share)	$ 0.10
Dividends	$ 44.7
FY 2019 second half dividend
Dividends Payable [Line Items]
Interim ordinary dividend to shareholders (in dollars per share)	$ 0.26
Dividends	$ 113.9
FY 2019 first half dividend
Dividends Payable [Line Items]
Interim ordinary dividend to shareholders (in dollars per share)	$ 0.10
Dividends	$ 43.6
FY 2018 second half dividend
Dividends Payable [Line Items]
Interim ordinary dividend to shareholders (in dollars per share)	$ 0.30
Dividends	$ 128.5

X

- Definition

Aggregate dividends paid during the period for each share of common stock outstanding.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.3-04)
-URI http://asc.fasb.org/extlink&oid=120397183&loc=d3e187085-122770

+ Details

Name:	us-gaap_CommonStockDividendsPerShareCashPaid
Namespace Prefix:	us-gaap_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

Name:	us-gaap_DividendsPayableLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Amount of cash outflow in the form of ordinary dividends to common shareholders of the parent entity.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 15
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=121586364&loc=d3e3291-108585

+ Details

Name:	us-gaap_PaymentsOfDividendsCommonStock
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

X

- Details

Name:	us-gaap_DividendsAxis=jhx_FiscalYearTwoThousandAndTwentyOneSpecialDividendMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_DividendsAxis=jhx_FiscalYearTwoThousandAndTwentyFirstHalfDividendMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_DividendsAxis=jhx_FiscalYearTwoThousandAndNineteenSecondHalfDividendMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_DividendsAxis=jhx_FiscalYearTwoThousandAndNineteenFirstHalfDividendMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_DividendsAxis=jhx_FiscalYearTwoThousandAndEighteenSecondHalfDividendMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: