Condensed Consolidated Statement Of Cash Flows (Parenthetical) - Maturity Greater Than Three Months [Member] - USD ($) $ in Billions	6 Months Ended
Jun. 30, 2020	Jun. 30, 2019
Net cash flow from issuance/(repayment) of commercial paper	$ 7.0	$ 6.5
Proceeds from issuance of commercial paper	20.5	12.3
Repayments of commercial paper	$ 13.5	$ 5.8

The net cash inflow or cash outflow from issuing (borrowing) and repaying commercial paper.

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 14
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=118932676&loc=d3e3255-108585

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 9
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=118932676&loc=d3e3098-108585

Reference 3: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 15
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=118932676&loc=d3e3291-108585

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