SCHEDULE I - CONDENSED PARENT COMPANY FINANCIAL STATEMENTS BALANCE SHEETS (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Assets
Cash and cash equivalents	$ 18.0	$ 16.8
Other current assets	57.5	55.9
Current assets	1,410.7	2,334.2
Total investments in subsidiaries, at equity	572.4	540.9
Property and equipment, net of accumulated depreciation of $1.2 and $1.4, respectively	6,859.8	6,206.2
Accumulated depreciation	3,343.1	3,221.0
Other long-term assets	270.1	145.4
Total assets	11,282.0	11,243.5	10,327.4
Liabilities and Equity
Short-term debt	317.6	326.0
Current portion of long-term debt	125.0	100.0
Accounts payable	490.7	401.9
Other current liabilities	261.4	218.9
Current liabilities	1,436.1	1,723.4
Long-term debt	2,956.3	2,956.2
Other long-term liabilities	168.7	127.1
Long-term liabilities	6,495.1	6,206.7
Total liabilities and equity	11,282.0	11,243.5
Integrys Energy Group, Inc.
Assets
Cash and cash equivalents	5.1	0.3	2.6	1.9
Accounts receivable from related parties	31.2	32.2
Interest receivable from related parties	4.8	4.1
Deferred income taxes	0.4	0.6
Notes receivable from related parties	51.6	84.9
Current portion of long-term notes receivable from related parties	2.5	10.0
Other current assets	49.1	47.8
Current assets	144.7	179.9
Total investments in subsidiaries, at equity	4,015.1	4,268.5
Notes receivable from related parties	180.9	224.3
Property and equipment, net of accumulated depreciation of $1.2 and $1.4, respectively	4.3	4.5
Accumulated depreciation	1.2	1.4
Receivables from related parties	19.2	18.3
Deferred income taxes	9.6	22.3
Other long-term assets	181.2	43.9
Total assets	4,555.0	4,761.7
Liabilities and Equity
Short-term notes payable to related parties	126.2	165.7
Short-term debt	7.2	123.2
Current portion of long-term debt	0	100.0
Accounts payable to related parties	5.8	0.9
Accounts payable	2.8	1.2
Deferred income taxes	6.2	6.4
Other current liabilities	43.2	2.8
Current liabilities	191.4	400.2
Long-term debt	974.7	974.7
Deferred income taxes	56.9	110.1
Other long-term liabilities	32.3	15.4
Long-term liabilities	1,063.9	1,100.2
Total common shareholders' equity	3,299.7	3,261.3
Total liabilities and equity	$ 4,555.0	$ 4,761.7