Summary of Significant Accounting Policies - Schedule of Impact of Adoption on Consolidated Statement of Cash Flows (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Cash flows from operating activities
Net income	$ 14	$ 321	$ 167	$ 325
Deferred income taxes			25	105
Changes in operating assets and liabilities:
Accounts receivable, net			(50)	(43)
Accounts payable and accrued liabilities			(94)	(84)
Royalty advances			(107)	0
Deferred revenue			(17)	0
Other balance sheet changes			(1)	(30)
Net cash provided by operating activities			249	265
Effect of exchange rate changes on cash and equivalents			(1)	(5)
Net decrease in cash and equivalents			27	258
Cash and equivalents at beginning of period			514	647
Cash and equivalents at end of period	541	$ 905	541	$ 905
Balances Without Adoption Of ASC 606 | Topic 606
Cash flows from operating activities
Net income	37		146
Deferred income taxes			15
Changes in operating assets and liabilities:
Accounts receivable, net			(28)
Accounts payable and accrued liabilities			(96)
Royalty advances			(104)
Deferred revenue			(15)
Other balance sheet changes			5
Net cash provided by operating activities			249
Effect of exchange rate changes on cash and equivalents			(1)
Net decrease in cash and equivalents			27
Cash and equivalents at beginning of period			514
Cash and equivalents at end of period	541		541
Impact of Adoption | Topic 606
Cash flows from operating activities
Net income	(23)		21
Deferred income taxes			10
Changes in operating assets and liabilities:
Accounts receivable, net			(22)
Accounts payable and accrued liabilities			2
Royalty advances			(3)
Deferred revenue			(2)
Other balance sheet changes			(6)
Net cash provided by operating activities			0
Effect of exchange rate changes on cash and equivalents			0
Net decrease in cash and equivalents			0
Cash and equivalents at beginning of period			0
Cash and equivalents at end of period	$ 0		$ 0