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

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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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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, 2019 AUD ($) yr	Jun. 30, 2019 GBP (£) yr	Jun. 30, 2019 USD ($)
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			$ 24.10
Estimated life of awards \| yr	3	3
Share price at grant date	$ 33.50
BHP Group Limited [member] \| Long-Term Incentive Plan [member]
Disclosure of terms and conditions of share-based payment arrangement [line items]
Weighted average fair value of awards granted during the year			17.36
Risk-free interest rate	2.04%	2.04%
Estimated life of awards \| yr	5	5
Share price at grant date	$ 33.50
Estimated volatility of share price	30.00%	30.00%
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			21.29
Dividend yield	5.30%	5.30%
BHP Group Limited [member] \| MAP awards [member] \| September 24, 2018 grant date [member]
Disclosure of terms and conditions of share-based payment arrangement [line items]
Share price at grant date	$ 33.83
BHP Group Limited [member] \| MAP awards [member] \| November 12, 2018 grant date [member]
Disclosure of terms and conditions of share-based payment arrangement [line items]
Share price at grant date	33.41
BHP Group Limited [member] \| MAP awards [member] \| December 18, 2018 grant date [member]
Disclosure of terms and conditions of share-based payment arrangement [line items]
Share price at grant date	$ 33.50
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] \| Shareplus [member]
Disclosure of terms and conditions of share-based payment arrangement [line items]
Weighted average fair value of awards granted during the year			20.68
Risk-free interest rate	2.13%	2.13%
Estimated life of awards \| yr	3	3
Share price at grant date	$ 28.29
Dividend yield	4.71%	4.71%
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			18.68
Share price at grant date \| £		£ 16.71
Dividend yield	5.80%	5.80%
BHP Group Plc [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 Plc [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 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			$ 14.71
Risk-free interest rate	0.86%	0.86%
Estimated life of awards \| yr	3	3
Share price at grant date \| £		£ 14.04
Dividend yield	5.40%	5.40%