CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Millions	3 Months Ended
Dec. 31, 2019	Dec. 31, 2018
Statement of Comprehensive Income [Abstract]
Net income	$ 379	$ 604
Investments available-for-sale:
Unrealized gain (loss)	(32)	16
Cash flow hedging instruments:
Reclassification adjustment for portion of realized loss amortized to net income	1	1
Total other comprehensive income (loss), before tax	(31)	17
Income tax effect	8	(4)
Total other comprehensive income (loss), net of tax	(23)	13
Comprehensive income	$ 356	$ 617

Amount after tax of increase (decrease) in equity from transactions and other events and circumstances from net income and other comprehensive income, attributable to parent entity. Excludes changes in equity resulting from investments by owners and distributions to owners.

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