STATEMENTS OF CAPITALIZATION (Parentheticals) (USD $) In Millions, except Per Share data, unless otherwise specified			12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2011 Garfield Industrial Authority, January 1, 2025 [Member]	Dec. 31, 2011 Muskogee Industrial Authority, January 1, 2025 [Member]	Dec. 31, 2011 Muskogee Industrial Authority, June 1, 2027 [Member]	Dec. 31, 2011 Series Due January 15, 2016 [Member] Senior Notes [Member]	Dec. 31, 2011 Series Due July 15, 2017 [Member] Senior Notes [Member]	Dec. 31, 2011 Series Due September 1, 2018 [Member] Senior Notes [Member]	Dec. 31, 2011 Series Due January 15, 2019 [Member] Senior Notes [Member]	Dec. 31, 2011 Series Due July 15, 2027 [Member] Senior Notes [Member]	Dec. 31, 2011 Series Due April 15, 2028 [Member] Senior Notes [Member]	Dec. 31, 2011 Series Due August 1, 2034 [Member] Senior Notes [Member]	Dec. 31, 2011 Series Due January 15, 2036 [Member] Senior Notes [Member]	Dec. 31, 2011 Series Due February 1, 2038 [Member] Senior Notes [Member]	Dec. 31, 2011 Series Due June 1, 2040 [Member] Senior Notes [Member]	Dec. 31, 2011 Series Due May 15, 2041 [Member] Senior Notes [Member]	Dec. 31, 2011 Debentures Subject to Mandatory Redemption [Member] Garfield Industrial Authority, January 1, 2025 [Member]	Dec. 31, 2011 Debentures Subject to Mandatory Redemption [Member] Muskogee Industrial Authority, January 1, 2025 [Member]	Dec. 31, 2011 Debentures Subject to Mandatory Redemption [Member] Muskogee Industrial Authority, June 1, 2027 [Member]
Common stock, par value (in dollars per share)	$ 2.50	$ 2.50
Common stock, shares authorized (in shares)	100.0
Common stock, shares outstanding (in shares)	40.4	40.4
Debt Instrument, maturity date			Jan. 01, 2025	Jan. 01, 2025	Jun. 01, 2027	Jan. 15, 2016	Jul. 15, 2017	Sep. 01, 2018	Jan. 15, 2019	Jul. 15, 2027	Apr. 15, 2028	Aug. 01, 2034	Jan. 15, 2036	Feb. 01, 2038	Jun. 01, 2040	May 15, 2041
Debt Instrument, Interest Rate, Stated Percentage Rate Range, Minimum																	0.22%	0.20%	0.24%
Debt Instrument, Interest Rate, Stated Percentage Rate Range, Maximum																	0.44%	0.44%	0.50%