Receivables (Receivables Sold Under The Agreement) (Details) - USD ($) $ in Millions	Sep. 30, 2021	Dec. 31, 2020
Receivables [Line Items]
Fair value of deferred proceeds	$ 164	$ 188
IPL [Member]
Receivables [Line Items]
Fair value of deferred proceeds	164	188
Receivables Sold [Member] | IPL [Member]
Receivables [Line Items]
Customer accounts receivable	145	114
Unbilled utility revenues	83	92
Receivables sold to third party	228	206
Less: cash proceeds	50	1
Deferred proceeds	178	205
Less: allowance for expected credit losses	14	17
Fair value of deferred proceeds	$ 164	$ 188