Commitments and Contingencies (Narrative) (Details) - USD ($)	1 Months Ended	3 Months Ended		6 Months Ended
	May 31, 2023	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022	May 04, 2023	Dec. 31, 2022	Jul. 01, 2021
Loss Contingencies [Line Items]
Reduction in deposit balance over 12 month period								$ 10,000,000,000
Additions (reductions) in deposit balance				$ 0
ID balance ceiling amount above fixed-rate obligation						$ 30,000,000,000
IDA balance floor amount						60,000,000,000
ID balance ceiling amount						90,000,000,000
Percentage of fixed rate investments								80.00%
Maximum buy down in fixed-rate obligation IDA balance						$ 5,000,000,000
Buy down of fixed-rate obligation amounts in deposits balance	$ 2,400,000,000
Market-based fee capitalized as a contract asset	$ 112,000,000	$ 111,000,000		111,000,000
Ending IDA balance		102,700,000,000		102,700,000,000			$ 122,600,000,000
Fixed-rate obligation IDA balance		96,400,000,000		96,400,000,000			108,500,000,000
Floating-rate obligation IDA balance		6,300,000,000		6,300,000,000			$ 14,100,000,000
Guarantees [Member]
Loss Contingencies [Line Items]
Liability for guarantees		0		0
Residential Real Estate [Member] | First Mortgage [Member]
Loss Contingencies [Line Items]
Purchased during period		854,000,000	$ 2,000,000,000	1,600,000,000	$ 4,700,000,000
Residential Real Estate [Member] | HELOCs [Member]
Loss Contingencies [Line Items]
Purchased during period		$ 52,000,000	$ 70,000,000	$ 95,000,000	$ 160,000,000