Employee Share-based Incentives - Compensation Expense (Details) - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2021	Mar. 31, 2020
Share-based Payment Arrangement [Abstract]
Cost of prior grants of RSUs, performance share units (“PSUs”) and stock options that are amortized over their applicable vesting periods	$ 356	$ 334
Accrual of estimated costs of share-based awards to be granted in future periods predominantly those to full-career eligible employees	548	310
Total noncash compensation expense related to employee share-based incentive plans	$ 904	$ 644

Amount of noncash expense for share-based payment arrangement.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=121586364&loc=d3e3602-108585

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration