Leases (Future Minimum Capital Lease Payments) (Details) (Scenario, Forecast [Member], WPL [Member], Sheboygan Falls Energy Facility [Member], USD $) In Millions, unless otherwise specified	Dec. 31, 2013
Scenario, Forecast [Member] \| WPL [Member] \| Sheboygan Falls Energy Facility [Member]
Schedule of Future Lease Payments for Capital Leases [Line Items]
2014	$ 15
2015	15
2016	15
2017	15
2018	15
Thereafter	98
Total estimated future minimum capital lease payments	173
Less: amount representing interest	74
Present value of minimum capital lease payments	$ 99

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Amount of minimum lease payments for capital leases.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 840

-SubTopic 30

-Section 50

-Paragraph 1

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=6455398&loc=d3e45280-112737

+ Details

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Amount of minimum lease payments maturing in the next fiscal year following the latest fiscal year for capital leases.

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Amount of minimum lease payments maturing in the fifth fiscal year following the latest fiscal year for capital leases.

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Amount of minimum lease payments maturing in the forth fiscal year following the latest fiscal year for capital leases.

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Amount of minimum lease payments maturing in the third fiscal year following the latest fiscal year for capital leases.

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Amount of minimum lease payments maturing in the second fiscal year following the latest fiscal year for capital leases.

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Amount of minimum lease payments maturing after the fifth fiscal year following the latest fiscal year for capital leases.

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Amount necessary to reduce net minimum lease payments to present value for capital leases.

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Present value of minimum lease payments for capital leases net of executory costs, including amounts paid by the lessee to the lessor for insurance, maintenance and taxes.

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