CONDENSED CONSOLIDATED BALANCE SHEETS - USD ($) $ in Millions	Mar. 31, 2021	Dec. 31, 2020
Current assets
Cash and cash equivalents	$ 26.1	$ 24.8
Accounts receivable and unbilled revenues, net of reserves of $259.1 and $220.1, respectively	1,369.9	1,202.8
Materials, supplies, and inventories	353.5	528.6
Prepayments	258.8	263.4
Amounts recoverable from customers	306.7	20.0
Other	40.5	43.4
Current assets	2,355.5	2,083.0
Long-term assets
Property, plant, and equipment, net of accumulated depreciation and amortization of $9,481.4 and $9,364.7, respectively	25,994.4	25,707.4
Regulatory assets	3,487.1	3,524.1
Equity investment in transmission affiliates	1,773.6	1,764.3
Goodwill	3,052.8	3,052.8
Other	937.2	896.5
Long-term assets	35,245.1	34,945.1
Total assets	37,600.6	37,028.1
Current liabilities
Short-term debt	1,580.4	1,776.9
Current portion of long-term debt	787.0	785.8
Accounts payable	656.0	880.7
Accrued payroll and benefits	123.0	174.0
Other	568.5	530.7
Current liabilities	3,714.9	4,148.1
Long-term liabilities
Long-term debt	12,317.7	11,728.1
Deferred income taxes	4,214.1	4,059.8
Deferred revenue, net	406.4	412.2
Regulatory liabilities	3,890.8	3,928.1
Environmental remediation liabilities	532.9	532.9
Pension and OPEB obligations	319.9	327.0
Other	1,236.3	1,229.4
Long-term liabilities	22,918.1	22,217.5
Commitments and contingencies (Note 20)
Common shareholders' equity
Common stock – $0.01 par value; 325,000,000 shares authorized; 315,434,531 shares outstanding	3.2	3.2
Additional paid in capital	4,143.6	4,143.7
Retained earnings	6,626.0	6,329.6
Accumulated other comprehensive loss	(5.7)	(6.8)
Common shareholders' equity	10,767.1	10,469.7
Preferred stock of subsidiary	30.4	30.4
Noncontrolling interests	170.1	162.4
Total liabilities and equity	$ 37,600.6	$ 37,028.1