Segment Reporting - Summary of Reportable Segments (Detail) - USD ($)
$ in Millions
 12 Months Ended
Jun. 30, 2021
Jun. 30, 2020
Jun. 30, 2019
Disclosure of reportable segments [line items]      
Revenue $ 60,817 $ 42,931 $ 44,288
Underlying EBITDA 37,379 22,071 23,158
Depreciation and amortisation (6,824) (6,112) (5,829)
Impairment losses (264) (85) (264)
Underlying EBIT 30,291 15,874 17,065
Exceptional items (4,385) (1,453) (952)
Net finance costs (1,305) (911) (1,064)
Profit before taxation 24,601 13,510 15,049
Capital expenditure (cash basis) 6,606 6,900 6,250
(Loss)/profit from equity accounted investments, related impairments and expenses (921) (512) (546)
Investments accounted for using the equity method 1,742 2,585 2,569
Total assets 108,927 105,733 101,811
Total liabilities 53,322 53,558 50,058
Revenue [member]      
Disclosure of reportable segments [line items]      
Revenue 60,817 42,931 44,288
Operating segments [member] | Petroleum [member]      
Disclosure of reportable segments [line items]      
Revenue 3,946 4,070 5,930
Underlying EBITDA 2,300 2,207 4,061
Depreciation and amortisation (1,739) (1,445) (1,560)
Impairment losses (128) (12) (21)
Underlying EBIT 433 750 2,480
Exceptional items (47) (6)  
Capital expenditure (cash basis) 994 909 645
(Loss)/profit from equity accounted investments, related impairments and expenses (6) (4) (2)
Investments accounted for using the equity method 253 245 239
Total assets 13,775 13,071 12,434
Total liabilities 5,811 4,824 4,102
Operating segments [member] | Petroleum [member] | Revenue [member]      
Disclosure of reportable segments [line items]      
Revenue 3,895 4,008 5,853
Operating segments [member] | Petroleum [member] | Inter-segment revenue [member]      
Disclosure of reportable segments [line items]      
Revenue 51 62 77
Operating segments [member] | Copper [member]      
Disclosure of reportable segments [line items]      
Revenue 15,726 10,666 10,838
Underlying EBITDA 8,489 4,347 4,550
Depreciation and amortisation (1,608) (1,740) (1,835)
Impairment losses (72) (17) (128)
Underlying EBIT 6,809 2,590 2,587
Exceptional items (144) (1,228)  
Capital expenditure (cash basis) 2,180 2,434 2,735
(Loss)/profit from equity accounted investments, related impairments and expenses 692 67 303
Investments accounted for using the equity method 1,482 1,558 1,472
Total assets 31,517 28,892 28,378
Total liabilities 4,589 3,535 3,340
Operating segments [member] | Copper [member] | Revenue [member]      
Disclosure of reportable segments [line items]      
Revenue 15,726 10,666 10,838
Operating segments [member] | Iron Ore [member]      
Disclosure of reportable segments [line items]      
Revenue 34,475 20,797 17,255
Underlying EBITDA 26,278 14,554 11,129
Depreciation and amortisation (1,971) (1,608) (1,653)
Impairment losses (13) (22) (79)
Underlying EBIT 24,294 12,924 9,397
Exceptional items (1,319) (614) (971)
Capital expenditure (cash basis) 2,188 2,328 1,611
(Loss)/profit from equity accounted investments, related impairments and expenses (1,126) (508) (945)
Total assets 26,171 23,841 22,592
Total liabilities 7,508 5,441 5,106
Operating segments [member] | Iron Ore [member] | Revenue [member]      
Disclosure of reportable segments [line items]      
Revenue 34,475 20,797 17,251
Operating segments [member] | Iron Ore [member] | Inter-segment revenue [member]      
Disclosure of reportable segments [line items]      
Revenue     4
Operating segments [member] | Coal [member]      
Disclosure of reportable segments [line items]      
Revenue 5,154 6,242 9,121
Underlying EBITDA 288 1,632 4,067
Depreciation and amortisation (845) (807) (632)
Impairment losses (20) (14) (35)
Underlying EBIT (577) 811 3,400
Exceptional items (1,567) (18)  
Capital expenditure (cash basis) 579 603 655
(Loss)/profit from equity accounted investments, related impairments and expenses (480) (68) 103
Investments accounted for using the equity method   776 853
Total assets 11,030 12,110 12,124
Total liabilities 3,518 2,601 2,450
Operating segments [member] | Coal [member] | Revenue [member]      
Disclosure of reportable segments [line items]      
Revenue 5,154 6,241 9,121
Operating segments [member] | Coal [member] | Inter-segment revenue [member]      
Disclosure of reportable segments [line items]      
Revenue   1  
Group and unallocated items/eliminations [member]      
Disclosure of reportable segments [line items]      
Revenue 1,516 1,156 1,144
Underlying EBITDA 24 (669) (649)
Depreciation and amortisation (661) (512) (149)
Impairment losses (31) (20) (1)
Underlying EBIT (668) (1,201) (799)
Exceptional items (1,308) 413 19
Capital expenditure (cash basis) 665 626 604
(Loss)/profit from equity accounted investments, related impairments and expenses (1) 1 (5)
Investments accounted for using the equity method 7 6 5
Total assets 26,434 27,819 26,283
Total liabilities 31,896 37,157 35,060
Group and unallocated items/eliminations [member] | Revenue [member]      
Disclosure of reportable segments [line items]      
Revenue 1,567 1,219 1,225
Group and unallocated items/eliminations [member] | Inter-segment revenue [member]      
Disclosure of reportable segments [line items]      
Revenue $ (51) $ (63) $ (81)