Statement Of Changes In Equity [Abstract]

Johnson Matthey PLC - Filing #1656099

Concept	2021-04-01 to 2022-03-31	2021-04-01 to 2022-03-31	2021-04-01 to 2022-03-31	2021-04-01 to 2022-03-31	2021-04-01 to 2022-03-31	As at 2022-03-31	As at 2022-03-31	As at 2022-03-31	As at 2022-03-31	2021-04-01 to 2022-03-31	As at 2022-03-31	As at 2022-03-31	As at 2021-03-31	As at 2021-03-31	As at 2021-03-31	As at 2021-03-31	As at 2021-03-31	2020-04-01 to 2021-03-31	2020-04-01 to 2021-03-31	As at 2021-03-31	2020-04-01 to 2021-03-31	2020-04-01 to 2021-03-31	2020-04-01 to 2021-03-31	2020-04-01 to 2021-03-31	As at 2020-03-31	As at 2020-03-31	As at 2020-03-31	As at 2020-03-31	As at 2020-03-31	As at 2020-03-31
Statement of changes in equity [abstract]
Statement of changes in equity [line items]
Equity	—	—	—	—	—	24,000,000 GBP	218,000,000 GBP	148,000,000 GBP	2,049,000,000 GBP	—	2,441,000,000 GBP	50,000,000 GBP	2,345,000,000 GBP	– GBP	2,685,000,000 GBP	221,000,000 GBP	148,000,000 GBP	—	—	2 9 GBP	—	—	—	—	142,000,000 GBP	2,824,000,000 GBP	32,000,000 GBP	148,000,000 GBP	221,000,000 GBP	2,345,000,000 GBP
Changes in equity [abstract]
Comprehensive income [abstract]
Profit (loss)	– GBP	101,000,000 GBP	– GBP	– GBP	– GBP	—	—	—	—	101,000,000 GBP	—	—	—	—	—	—	—	– GBP	– GBP	—	205,000,000 GBP	– GBP	– GBP	205,000,000 GBP	—	—	—	—	—	—
Other comprehensive income	—	—	—	—	—	—	—	—	—	189,000,000 GBP	—	—	—	—	—	—	—	—	—	—	255,000,000 GBP	—	—	—	—	—	—	—	—	—
Comprehensive income	– GBP	41,000,000 GBP	47,000,000 GBP	– GBP	– GBP	—	—	—	—	88,000,000 GBP	—	—	—	—	—	—	—	1 42 GBP	– GBP	—	50,000,000 GBP	– GBP	– GBP	92,000,000 GBP	—	—	—	—	—	—
Dividends recognised as distributions to owners	– GBP	139,000,000 GBP	– GBP	– GBP	– GBP	—	—	—	—	1 39 GBP	—	—	—	—	—	—	—	– GBP	– GBP	—	9 9 GBP	– GBP	– GBP	99,000,000 GBP	—	—	—	—	—	—
Increase (decrease) through share-based payment transactions, equity	– GBP	15,000,000 GBP	– GBP	– GBP	– GBP	—	—	—	—	15,000,000 GBP	—	—	—	—	—	—	—	– GBP	– GBP	—	16,000,000 GBP	– GBP	– GBP	16,000,000 GBP	—	—	—	—	—	—