Fair Value Measurements (Recurring Fair Value Measurements) (Details) - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021
Assets:
Money market fund investments	$ 10	$ 32
Deferred proceeds	185	214
Liabilities and equity:
Long-term debt (including current maturities)	7,339	8,330
Commodity Contracts [Member]
Assets:
Derivatives	237	176
Liabilities and equity:
Derivatives	79	9
Level 1 [Member]
Assets:
Money market fund investments	10	32
Deferred proceeds	0	0
Liabilities and equity:
Long-term debt (including current maturities)	0	0
Level 1 [Member] | Commodity Contracts [Member]
Assets:
Derivatives	0	0
Liabilities and equity:
Derivatives	0	0
Level 2 [Member]
Assets:
Money market fund investments	0	0
Deferred proceeds	0	0
Liabilities and equity:
Long-term debt (including current maturities)	7,338	8,329
Level 2 [Member] | Commodity Contracts [Member]
Assets:
Derivatives	206	146
Liabilities and equity:
Derivatives	67	8
Level 3 [Member]
Assets:
Money market fund investments	0	0
Deferred proceeds	185	214
Liabilities and equity:
Long-term debt (including current maturities)	1	1
Level 3 [Member] | Commodity Contracts [Member]
Assets:
Derivatives	31	30
Liabilities and equity:
Derivatives	12	1
Carrying Amount [Member]
Assets:
Money market fund investments	10	32
Deferred proceeds	185	214
Liabilities and equity:
Long-term debt (including current maturities)	8,076	7,368
Carrying Amount [Member] | Commodity Contracts [Member]
Assets:
Derivatives	237	176
Liabilities and equity:
Derivatives	79	9
IPL [Member]
Assets:
Money market fund investments	10	32
Deferred proceeds	185	214
Liabilities and equity:
Long-term debt (including current maturities)	3,228	4,124
IPL [Member] | Commodity Contracts [Member]
Assets:
Derivatives	138	84
Liabilities and equity:
Derivatives	46	4
IPL [Member] | Level 1 [Member]
Assets:
Money market fund investments	10	32
Deferred proceeds	0	0
Liabilities and equity:
Long-term debt (including current maturities)	0	0
IPL [Member] | Level 1 [Member] | Commodity Contracts [Member]
Assets:
Derivatives	0	0
Liabilities and equity:
Derivatives	0	0
IPL [Member] | Level 2 [Member]
Assets:
Money market fund investments	0	0
Deferred proceeds	0	0
Liabilities and equity:
Long-term debt (including current maturities)	3,228	4,124
IPL [Member] | Level 2 [Member] | Commodity Contracts [Member]
Assets:
Derivatives	111	65
Liabilities and equity:
Derivatives	35	3
IPL [Member] | Level 3 [Member]
Assets:
Money market fund investments	0	0
Deferred proceeds	185	214
Liabilities and equity:
Long-term debt (including current maturities)	0	0
IPL [Member] | Level 3 [Member] | Commodity Contracts [Member]
Assets:
Derivatives	27	19
Liabilities and equity:
Derivatives	11	1
IPL [Member] | Carrying Amount [Member]
Assets:
Money market fund investments	10	32
Deferred proceeds	185	214
Liabilities and equity:
Long-term debt (including current maturities)	3,646	3,643
IPL [Member] | Carrying Amount [Member] | Commodity Contracts [Member]
Assets:
Derivatives	138	84
Liabilities and equity:
Derivatives	46	4
WPL [Member]
Liabilities and equity:
Long-term debt (including current maturities)	2,542	2,862
WPL [Member] | Commodity Contracts [Member]
Assets:
Derivatives	99	92
Liabilities and equity:
Derivatives	33	5
WPL [Member] | Level 1 [Member]
Liabilities and equity:
Long-term debt (including current maturities)	0	0
WPL [Member] | Level 1 [Member] | Commodity Contracts [Member]
Assets:
Derivatives	0	0
Liabilities and equity:
Derivatives	0	0
WPL [Member] | Level 2 [Member]
Liabilities and equity:
Long-term debt (including current maturities)	2,542	2,862
WPL [Member] | Level 2 [Member] | Commodity Contracts [Member]
Assets:
Derivatives	95	81
Liabilities and equity:
Derivatives	32	5
WPL [Member] | Level 3 [Member]
Liabilities and equity:
Long-term debt (including current maturities)	0	0
WPL [Member] | Level 3 [Member] | Commodity Contracts [Member]
Assets:
Derivatives	4	11
Liabilities and equity:
Derivatives	1	0
WPL [Member] | Carrying Amount [Member]
Liabilities and equity:
Long-term debt (including current maturities)	2,770	2,429
WPL [Member] | Carrying Amount [Member] | Commodity Contracts [Member]
Assets:
Derivatives	99	92
Liabilities and equity:
Derivatives	$ 33	$ 5