Leases (Finance Lease) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Leases [Line Items]
Finance lease assets, Property, plant and equipment, net	$ 133	$ 11
Finance lease liabilities, Other current liabilities	5	1
Finance lease liabilities, Other liabilities	131	11
Finance lease liabilities, Total	$ 136	$ 12
Finance lease, Remaining lease term	34 years	34 years
Finance lease, Discount rate, percent	5.00%	3.00%
Finance lease, Depreciation expense	$ 0	$ 0	$ 0
Finance lease, Interest expense	3	0	0
Finance lease, Total expense	$ 3	$ 0	0
Finance Lease, Right-of-Use Asset, Statement of Financial Position [Extensible Enumeration]	Property, plant and equipment, net	Property, plant and equipment, net
Finance Lease, Liability, Current, Statement of Financial Position [Extensible Enumeration]	Other	Other
Finance Lease, Liability, Noncurrent, Statement of Financial Position [Extensible Enumeration]	Other	Other
Sheboygan Falls Energy Facility [Member]
Leases [Line Items]
Finance Lease, Right-of-Use Asset, Statement of Financial Position [Extensible Enumeration]	Property, plant and equipment, net	Property, plant and equipment, net
Finance Lease, Liability, Current, Statement of Financial Position [Extensible Enumeration]	Other	Other
Finance Lease, Liability, Noncurrent, Statement of Financial Position [Extensible Enumeration]	Other	Other
Leased land for solar generation [Member]
Leases [Line Items]
Finance lease assets, Property, plant and equipment, net	$ 133	$ 11
Finance lease liabilities, Other current liabilities	5	1
Finance lease liabilities, Other liabilities	$ 131	$ 11
Finance Lease, Right-of-Use Asset, Statement of Financial Position [Extensible Enumeration]	Property, plant and equipment, net	Property, plant and equipment, net
Finance Lease, Liability, Current, Statement of Financial Position [Extensible Enumeration]	Other	Other
Finance Lease, Liability, Noncurrent, Statement of Financial Position [Extensible Enumeration]	Other	Other
WPL [Member]
Leases [Line Items]
Finance lease assets, Property, plant and equipment, net	$ 148	$ 32
Finance lease liabilities, Other current liabilities	17	11
Finance lease liabilities, Other liabilities	150	42
Finance lease liabilities, Total	$ 167	$ 53
Finance lease, Remaining lease term	28 years	10 years
Finance lease, Discount rate, percent	5.00%	9.00%
Finance lease, Depreciation expense	$ 6	$ 6	6
Finance lease, Interest expense	7	5	6
Finance lease, Total expense	13	11	$ 12
WPL [Member] | Sheboygan Falls Energy Facility [Member]
Leases [Line Items]
Finance lease assets, Property, plant and equipment, net	15	21
Finance lease liabilities, Other current liabilities	12	10
Finance lease liabilities, Other liabilities	19	31
WPL [Member] | Leased land for solar generation [Member]
Leases [Line Items]
Finance lease assets, Property, plant and equipment, net	133	11
Finance lease liabilities, Other current liabilities	5	1
Finance lease liabilities, Other liabilities	$ 131	$ 11