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Equity - Narrative (Details) - USD ($) shares in Millions, $ in Millions		1 Months Ended	3 Months Ended		7 Months Ended
	Oct. 29, 2018	Apr. 30, 2019	Mar. 31, 2019	Mar. 31, 2018	Apr. 30, 2019	Oct. 25, 2018
Accelerated Share Repurchases [Line Items]
Treasury stock shares acquired			$ 1,090	$ 566
Accelerated Share Repurchase Agreement
Accelerated Share Repurchases [Line Items]
Share repurchase program authorized amount						$ 5,000
Treasury stock shares purchased (in shares)	56.7
Payment under ASR agreement	$ 5,000
Treasury stock shares acquired	4,000
Decrease in other-paid-in capital	$ 1,000
Subsequent Event | Accelerated Share Repurchase Agreement
Accelerated Share Repurchases [Line Items]
Treasury stock shares purchased (in shares)		7.7			64.4

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