Financial Instruments and Fair Value Measurements - Summary of Mandatorily Redeemable Noncontrolling Interest Liabilities Classified Level 3 (Detail) $ in Millions, $ in Millions			1 Months Ended		12 Months Ended
	Jul. 31, 2017 USD ($)	Jul. 31, 2017 AUD ($)	Jul. 31, 2019 USD ($)	Jul. 31, 2019 AUD ($)	Jun. 30, 2020 USD ($)	Jun. 30, 2019 USD ($)
Smartline Home Loans Pty Limited
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Non-controlling ownership percentage	19.70%	19.70%
Business acquisition, cost of acquired entity, cash paid	$ 55	$ 70
Smartline Home Loans Pty Limited | ReaGroup Limited
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Non-controlling ownership percentage			19.70%	19.70%
Business acquisition, cost of acquired entity, cash paid				$ 11
Financial Instruments Subject To Mandatory Redemption Settlement Terms Share Value
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance—beginning of period			$ 11		$ 11	$ 12
Payments					11	0
Measurement adjustments					0	(4)
Accretion					0	4
Foreign exchange movements					0	(1)
Balance—end of period					$ 0	$ 11