Employee Share Ownership Plans - Summary of Fair Value and Assumptions in the Calculation of Fair Value for Awards Issued (Detail) - 12 months ended Jun. 30, 2021	USD ($) yr $ / shares	USD ($) yr £ / shares
BHP Group Limited [member] \| CDP awards [Member]
Disclosure of terms and conditions of share-based payment arrangement [line items]
Weighted average fair value of awards granted during the year \| $	$ 25.28	$ 25.28
Share price at grant date	$ 35.90
BHP Group Limited [member] \| CDP awards [Member] \| Bottom of range [member]
Disclosure of terms and conditions of share-based payment arrangement [line items]
Estimated life of awards \| yr	2	2
BHP Group Limited [member] \| CDP awards [Member] \| Top of range [member]
Disclosure of terms and conditions of share-based payment arrangement [line items]
Estimated life of awards \| yr	5	5
BHP Group Limited [member] \| STIP awards [member]
Disclosure of terms and conditions of share-based payment arrangement [line items]
Weighted average fair value of awards granted during the year \| $	$ 25.28	$ 25.28
Estimated life of awards \| yr	2	2
Share price at grant date	$ 35.90
BHP Group Limited [member] \| LTIP awards [member]
Disclosure of terms and conditions of share-based payment arrangement [line items]
Weighted average fair value of awards granted during the year \| $	$ 14.68	$ 14.68
Risk-free interest rate	0.25%	0.25%
Estimated life of awards \| yr	5	5
Estimated volatility of share price	28.00%	28.00%
BHP Group Limited [member] \| LTIP awards [member] \| Range One [Member]
Disclosure of terms and conditions of share-based payment arrangement [line items]
Share price at grant date	$ 35.90
BHP Group Limited [member] \| LTIP awards [member] \| Range Two [Member]
Disclosure of terms and conditions of share-based payment arrangement [line items]
Share price at grant date	33.81
BHP Group Limited [member] \| LTIP awards [member] \| Range Three [Member]
Disclosure of terms and conditions of share-based payment arrangement [line items]
Share price at grant date	$ 38.56
BHP Group Limited [member] \| MAP awards [member]
Disclosure of terms and conditions of share-based payment arrangement [line items]
Weighted average fair value of awards granted during the year \| $	$ 22.88	$ 22.88
Dividend yield	4.90%	4.90%
BHP Group Limited [member] \| MAP awards [member] \| Bottom of range [member]
Disclosure of terms and conditions of share-based payment arrangement [line items]
Estimated life of awards \| yr	1	1
BHP Group Limited [member] \| MAP awards [member] \| Top of range [member]
Disclosure of terms and conditions of share-based payment arrangement [line items]
Estimated life of awards \| yr	5	5
BHP Group Limited [member] \| MAP awards [member] \| Range One [Member]
Disclosure of terms and conditions of share-based payment arrangement [line items]
Share price at grant date	$ 38.36
BHP Group Limited [member] \| MAP awards [member] \| Range Two [Member]
Disclosure of terms and conditions of share-based payment arrangement [line items]
Share price at grant date	36.91
BHP Group Limited [member] \| MAP awards [member] \| Range Three [Member]
Disclosure of terms and conditions of share-based payment arrangement [line items]
Share price at grant date	35.90
BHP Group Limited [member] \| MAP awards [member] \| Range Four [Member]
Disclosure of terms and conditions of share-based payment arrangement [line items]
Share price at grant date	$ 45.88
BHP Group Limited [member] \| Shareplus [member]
Disclosure of terms and conditions of share-based payment arrangement [line items]
Weighted average fair value of awards granted during the year \| $	$ 24.96	$ 24.96
Risk-free interest rate	0.21%	0.21%
Estimated life of awards \| yr	3	3
Share price at grant date	$ 30.19
Dividend yield	5.59%	5.59%
BHP Group Limited [member] \| Transitional and Commencement KMP awards [Member]
Disclosure of terms and conditions of share-based payment arrangement [line items]
Weighted average fair value of awards granted during the year \| $	$ 28.35	$ 28.35
Estimated life of awards \| yr	2	2
Share price at grant date	$ 38.56
BHP Group Plc [member] \| MAP awards [member]
Disclosure of terms and conditions of share-based payment arrangement [line items]
Weighted average fair value of awards granted during the year \| $	$ 18.66	$ 18.66
Estimated life of awards \| yr	3	3
Share price at grant date \| £ / shares		$ 17.13
Dividend yield	5.70%	5.70%
BHP Group Plc [member] \| Shareplus [member]
Disclosure of terms and conditions of share-based payment arrangement [line items]
Weighted average fair value of awards granted during the year \| $	$ 15.32	$ 15.32
Risk-free interest rate	0.12%	0.12%
Estimated life of awards \| yr	3	3
Share price at grant date \| £ / shares		$ 12.11
Dividend yield	6.40%	6.40%

The expected volatility of the share price used to calculate the fair value of the share options granted. Expected volatility is a measure of the amount by which a price is expected to fluctuate during a period. The measure of volatility used in option pricing models is the annualised standard deviation of the continuously compounded rates of return on the share over a period of time.

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The option life of share options granted.

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The implied yield currently available on zero-coupon government issues of the country in whose currency the exercise price for share options granted is expressed, with a remaining term equal to the expected term of the option being valued (based on the option's remaining contractual life and taking into account the effects of expected early exercise). [Refer: Government [member]]

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The percentage of an expected dividend used to calculate the fair value of share options granted.

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The weighted average fair value of share options granted during the period at the measurement date. [Refer: Weighted average [member]]

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The weighted average share price used as input to the option pricing model to calculate the fair value of share options granted. [Refer: Option pricing model [member]; Weighted average [member]]

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