Leases (Expected Maturities of Operating and Finance Lease Liabilities (Details) - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021
Leases [Line Items]
Operating Leases Liability, 2023	$ 3
Operating Leases Liability, 2024	2
Operating Leases Liability, 2025	2
Operating Leases Liability, 2026	2
Operating Leases Liability, 2027	2
Operating Leases Liability, Thereafter	9
Operating Leases Liability, Total	20
Operating Leases Liability, Less: amount representing interest	4
Operating Leases Liability, Present value of minimum lease payments	16	$ 14
Finance Lease Liability, 2023	5
Finance Lease Liability, 2024	6
Finance Lease Liability, 2025	6
Finance Lease Liability, 2026	6
Finance Lease Liability, 2027	6
Finance Lease Liability, Thereafter	262
Finance Lease Liability, Total	291
Finance Lease Liability, Less: amount representing interest	155
Finance Lease Liability, Present value of minimum lease payments	136	12
IPL [Member]
Leases [Line Items]
Operating Leases Liability, 2023	1
Operating Leases Liability, 2024	1
Operating Leases Liability, 2025	1
Operating Leases Liability, 2026	1
Operating Leases Liability, 2027	1
Operating Leases Liability, Thereafter	6
Operating Leases Liability, Total	11
Operating Leases Liability, Less: amount representing interest	2
Operating Leases Liability, Present value of minimum lease payments	9	9
WPL [Member]
Leases [Line Items]
Operating Leases Liability, 2023	1
Operating Leases Liability, 2024	1
Operating Leases Liability, 2025	1
Operating Leases Liability, 2026	1
Operating Leases Liability, 2027	1
Operating Leases Liability, Thereafter	2
Operating Leases Liability, Total	7
Operating Leases Liability, Less: amount representing interest	1
Operating Leases Liability, Present value of minimum lease payments	6	5
Finance Lease Liability, 2023	20
Finance Lease Liability, 2024	21
Finance Lease Liability, 2025	12
Finance Lease Liability, 2026	6
Finance Lease Liability, 2027	6
Finance Lease Liability, Thereafter	262
Finance Lease Liability, Total	327
Finance Lease Liability, Less: amount representing interest	160
Finance Lease Liability, Present value of minimum lease payments	$ 167	$ 53