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Net Recognized Gains (Losses) on Equity Investments (Detail) - USD ($)
$ in Millions
 3 Months Ended 6 Months Ended
Dec. 31, 2021
Dec. 31, 2020
Dec. 31, 2021
Dec. 31, 2020
Schedule Of Gain Loss On Investments Including Marketable Securities And Investments Held At Cost Income Statement Reported Amounts Summary [Line Items]        
Net realized gains on investments sold $ 31 $ 16 $ 68 $ 33
Net unrealized gains on investments still held 268 326 593 426
Total 300 359 671 484
Equity Securities        
Schedule Of Gain Loss On Investments Including Marketable Securities And Investments Held At Cost Income Statement Reported Amounts Summary [Line Items]        
Impairments of investments 0 (2) 0 (11)
Total $ 299 $ 340 $ 661 $ 448