Other Earning Assets (Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2020	Dec. 31, 2019
Investments, Debt and Equity Securities [Abstract]
Equity Securities, FV-NI	$ 388	$ 450
Equity Securities, FV-NI, Unrealized Loss	$ 12

Amount of unrealized loss on investment in equity security measured at fair value with change in fair value recognized in net income (FV-NI).

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 321
-SubTopic 10
-Section 50
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=120269885&loc=SL75117546-209714

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