Number of shares that have been repurchased during the period and are being held in treasury.

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Name:	us-gaap_TreasuryStockSharesAcquired
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

Earnings Per Share (Narrative) (Details) - USD ($) shares in Millions, $ in Millions	3 Months Ended	9 Months Ended
	Mar. 31, 2020	Sep. 30, 2020	Sep. 30, 2019
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Repurchase of common stock		$ 5,483	$ 409
Stock Repurchase Program
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Repurchase of common stock	$ 4,000
Repurchase of common stock (in shares)	104.8