CONDENSED CONSOLIDATED BALANCE SHEETS - USD ($) $ in Millions	Sep. 30, 2017	Dec. 31, 2016
Current assets
Cash and cash equivalents	$ 18.1	$ 37.5
Accounts receivable and unbilled revenues, net of reserves of $112.7 and $108.0, respectively	948.0	1,241.7
Materials, supplies, and inventories	672.2	587.6
Prepayments	142.0	204.4
Other	43.0	97.5
Current assets	1,823.3	2,168.7
Long-term assets
Property, plant, and equipment, net of accumulated depreciation of $8,525.5 and $8,214.6, respectively	20,882.9	19,915.5
Regulatory assets	3,107.7	3,087.9
Equity investment in transmission affiliate	1,560.8	1,443.9
Goodwill	3,053.5	3,046.2
Other	584.8	461.0
Long-term assets	29,189.7	27,954.5
Total assets	31,013.0	30,123.2
Current liabilities
Short-term debt	993.5	860.2
Current portion of long-term debt	709.3	157.2
Accounts payable	743.9	861.5
Accrued payroll and benefits	136.8	163.8
Other	442.6	388.9
Current liabilities	3,026.1	2,431.6
Long-term liabilities
Long-term debt	8,785.8	9,158.2
Deferred income taxes	5,616.0	5,146.6
Deferred revenue, net	549.2	566.2
Regulatory liabilities	1,534.9	1,563.8
Environmental remediation liabilities	617.7	633.6
Pension and OPEB obligations	463.2	498.6
Other	1,194.4	1,164.4
Long-term liabilities	18,761.2	18,731.4
Commitments and contingencies (Note 17)
Common shareholders' equity
Common stock – $0.01 par value; 325,000,000 shares authorized; 315,575,562 and 315,614,941 shares outstanding, respectively	3.2	3.2
Additional paid in capital	4,281.4	4,309.8
Retained earnings	4,908.3	4,613.9
Accumulated other comprehensive income	2.4	2.9
Common shareholders' equity	9,195.3	8,929.8
Preferred stock of subsidiary	30.4	30.4
Total liabilities and equity	$ 31,013.0	$ 30,123.2