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Equity - Narrative (Details) - USD ($) shares in Millions, $ in Millions		1 Months Ended	3 Months Ended		6 Months Ended		9 Months Ended
	Oct. 29, 2018	Apr. 30, 2019	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Oct. 25, 2018
Accelerated Share Repurchases [Line Items]
Treasury stock shares acquired			$ 1,235	$ 1,596	$ 2,325	$ 2,162
Accelerated Share Repurchase Agreement
Accelerated Share Repurchases [Line Items]
Share repurchase program authorized amount								$ 5,000
Treasury stock shares purchased (in shares)	56.7	7.7					64.4
Payment under ASR agreement	$ 5,000
Treasury stock shares acquired	4,000
Decrease in other-paid-in capital	$ 1,000

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Amount of cash receipt from (payment to) bank; or stock received from (issuance to) bank in the settlement of the accelerated share repurchase agreement.

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Equity impact of the cost of common and preferred stock that were repurchased during the period. Recorded using the cost method.

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