Financial Instruments (Offsetting of Financial Assets and Financial Liabilities) (Details) - USD ($) $ in Millions	Mar. 31, 2020	Dec. 31, 2019
Offsetting of Assets
Gross Amounts of Recognized Assets	$ 588	$ 365
Gross Amounts Offset in the Consolidated Balance Sheets	(84)	(21)
Net Presented in the Consolidated Balance Sheets	504	344
Financial Instruments	(115)	(88)
Cash Collateral Received	(326)	(234)
Non-Cash Collateral Received	(27)	0
Net Assets Exposed	36	22
Offsetting of Liabilities
Gross Amounts of Recognized Liabilities	270	390
Gross Amounts Offset in the Consolidated Balance Sheets	(84)	(21)
Net Presented in the Consolidated Balance Sheets	186	369
Financial Instruments	(115)	(88)
Cash Collateral Pledged	0	0
Non-Cash Collateral Pledged	(8)	0
Net Liabilities	$ 63	$ 281

Fair value of liability associated with financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4B
-Subparagraph (a),(c)
-URI http://asc.fasb.org/extlink&oid=109980867&loc=SL5624163-113959

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 20
-Section 55
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=99393222&loc=SL20226003-175313

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 20
-Section 50
-Paragraph 3
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=51824906&loc=SL20225862-175312