Leases (Operating Leases) (Details) - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021
Leases [Line Items]
Operating leases assets, Property, plant and equipment, net	$ 16	$ 14
Operating leases liabilities, Other current liabilities	3	2
Operating leases liabilities, Other liabilities	13	12
Operating leases liabilities, Total	$ 16	$ 14
Operating leases, Weighted average remaining lease term	10 years	9 years
Operating leases, Weighted average discount rate, percent	4.00%	4.00%
Operating Lease, Right-of-Use Asset, Statement of Financial Position [Extensible Enumeration]	Property, plant and equipment, net	Property, plant and equipment, net
Operating Lease, Liability, Current, Statement of Financial Position [Extensible List]	Other	Other
Operating Lease, Liability, Noncurrent, Statement of Financial Position [Extensible List]	Other	Other
IPL [Member]
Leases [Line Items]
Operating leases assets, Property, plant and equipment, net	$ 9	$ 9
Operating leases liabilities, Other current liabilities	1	1
Operating leases liabilities, Other liabilities	8	8
Operating leases liabilities, Total	$ 9	$ 9
Operating leases, Weighted average remaining lease term	11 years	11 years
Operating leases, Weighted average discount rate, percent	4.00%	4.00%
WPL [Member]
Leases [Line Items]
Operating leases assets, Property, plant and equipment, net	$ 6	$ 5
Operating leases liabilities, Other current liabilities	1	1
Operating leases liabilities, Other liabilities	5	4
Operating leases liabilities, Total	$ 6	$ 5
Operating leases, Weighted average remaining lease term	9 years	8 years
Operating leases, Weighted average discount rate, percent	4.00%	4.00%