Financial Instruments (Offsetting of Financial Assets and Financial Liabilities) (Details) - USD ($) $ in Millions	Jun. 30, 2020	Dec. 31, 2019
Offsetting of Assets
Gross Amounts of Recognized Assets	$ 397	$ 365
Gross Amounts Offset in the Consolidated Balance Sheets	(35)	(21)
Net Presented in the Consolidated Balance Sheets	362	344
Financial Instruments	(203)	(88)
Cash Collateral Received	(101)	(234)
Non-Cash Collateral Received	(22)	0
Net Assets Exposed	36	22
Offsetting of Liabilities
Gross Amounts of Recognized Liabilities	535	390
Gross Amounts Offset in the Consolidated Balance Sheets	(35)	(21)
Net Presented in the Consolidated Balance Sheets	500	369
Financial Instruments	(203)	(88)
Cash Collateral Pledged	(2)	0
Non-Cash Collateral Pledged	(263)	0
Net Liabilities	$ 32	$ 281