CONDENSED CONSOLIDATED BALANCE SHEETS (Unaudited) - USD ($) $ in Millions	Mar. 31, 2017	Dec. 31, 2016
Current assets
Cash and cash equivalents	$ 45.7	$ 37.5
Accounts receivable and unbilled revenues, net of reserves of $123.1 and $108.0, respectively	1,191.4	1,241.7
Materials, supplies, and inventories	417.1	587.6
Prepayments	161.8	204.4
Other	39.3	97.5
Current assets	1,855.3	2,168.7
Long-term assets
Property, plant, and equipment, net of accumulated depreciation of $8,312.8 and $8,214.6, respectively	19,990.2	19,915.5
Regulatory assets	3,084.1	3,087.9
Equity investment in transmission affiliate	1,513.3	1,443.9
Goodwill	3,046.2	3,046.2
Other	527.5	461.0
Long-term assets	28,161.3	27,954.5
Total assets	30,016.6	30,123.2
Current liabilities
Short-term debt	670.4	860.2
Current portion of long-term debt	158.0	157.2
Accounts payable	582.3	861.5
Accrued payroll and benefits	107.5	163.8
Accrued interest	115.1	67.0
Other	421.3	321.9
Current liabilities	2,054.6	2,431.6
Long-term liabilities
Long-term debt	9,143.6	9,158.2
Deferred income taxes	5,287.4	5,146.6
Deferred revenue, net	561.0	566.2
Regulatory liabilities	1,563.4	1,563.8
Environmental remediation liabilities	630.7	633.6
Pension and OPEB obligations	458.9	498.6
Other	1,161.0	1,164.4
Long-term liabilities	18,806.0	18,731.4
Commitments and contingencies (Note 14)
Common shareholders' equity
Common stock – $0.01 par value; 325,000,000 shares authorized; 315,579,222 and 315,614,941 shares outstanding, respectively	3.2	3.2
Additional paid in capital	4,297.7	4,309.8
Retained earnings	4,822.0	4,613.9
Accumulated other comprehensive income	2.7	2.9
Common shareholders' equity	9,125.6	8,929.8
Preferred stock of subsidiary	30.4	30.4
Total liabilities and equity	$ 30,016.6	$ 30,123.2