Consolidated Statements of Capitalization (USD $)	Dec. 31, 2014	Dec. 31, 2013
Maturity
Total long term debt payable to affiliated trusts	$ 206,000,000	$ 206,000,000
Long Term Debt Maturities Repayments of Principal in Last Twelve Months	0	428,000,000
Long-term Debt, Maturities, Repayments of Principal in Next Twelve Months	2,375,000,000	2,375,000,000
Long-term debt maturities, 2016	1,360,000,000	1,360,000,000
Long-term Debt, Maturities, Repayments of Principal in Year Three	1,495,000,000	1,095,000,000
Long-term Debt, Maturities, Repayments of Principal in Year Four	850,000,000	850,000,000
Long-term Debt, Maturities, Repayments of Principal in Year Five	1,175,000,000	825,000,000
Long-term debt maturities, thereafter	10,574,000,000	9,973,000,000
Long-term senior notes and debt:
Total long -term senior notes and debt	19,054,000,000so_LongTermSeniorNotesAndDebt	17,892,000,000so_LongTermSeniorNotesAndDebt
Pollution control revenue bonds --
Total other long -term debt	4,719,000,000us-gaap_OtherLongTermDebt	3,503,000,000us-gaap_OtherLongTermDebt
Capitalized lease obligations	159,000,000us-gaap_CapitalLeaseObligations	163,000,000us-gaap_CapitalLeaseObligations
Unamortized debt premium (related to plant acquisition)	69,000,000	79,000,000
Unamortized debt discount	(33,000,000)	(30,000,000)
Total long-term debt (annual interest requirement )	24,174,000,000	21,813,000,000
Less amount due within one year	3,333,000,000	469,000,000
Long-term debt excluding amount due within one year	20,841,000,000	21,344,000,000
Percent capitalization	49.40%	51.50%
Redeemable Preferred and Preference Stock:
Redeemable preferred stock	375,000,000	375,000,000
Total redeemable preferred stock - percent capitalization	0.90%	0.90%
Preferred and preference stock of subsidiaries	977,000,000us-gaap_MinorityInterest	756,000,000us-gaap_MinorityInterest
Total preferred and preference stock of subsidiaries - percent capitalization	2.30%	1.80%
Redeemable Noncontrolling Interest, Equity, Carrying Amount	39,000,000	0
Redeemable Noncontrolling Interest As Percent Of Capitalization	0.10%	0.00%
Common Stockholders' Equity:
Common stock	4,539,000,000us-gaap_CommonStockValue	4,461,000,000us-gaap_CommonStockValue
Paid-in capital	5,955,000,000	5,362,000,000
Treasury, at cost	(26,000,000)us-gaap_TreasuryStockValue	(250,000,000)us-gaap_TreasuryStockValue
Retained earnings	9,609,000,000	9,510,000,000
Accumulated other comprehensive loss	(128,000,000)	(75,000,000)
Total Common Stockholders' Equity	19,949,000,000us-gaap_StockholdersEquity	19,008,000,000us-gaap_StockholdersEquity
Total common stockholders' equity - percent capitalization	47.30%	45.80%
Total stockholders' equity	20,926,000,000	19,764,000,000
Total Capitalization	42,181,000,000	41,483,000,000
Percent Capitalization	100.00%so_CapitalizationInPercent	100.00%so_CapitalizationInPercent
Redeemable Preferred Stock, $100 par or stated value [Member] \| Cumulative Preferred Stock [Member]
Redeemable Preferred and Preference Stock:
Redeemable preferred stock	81,000,000	81,000,000
Redeemable Preferred Stock, $1 par value [Member] \| Cumulative Preferred Stock [Member]
Redeemable Preferred and Preference Stock:
Redeemable preferred stock	294,000,000	294,000,000
Noncumulative Preferred Stock [Member]
Redeemable Preferred and Preference Stock:
Preferred and preference stock of subsidiaries	45,000,000	45,000,000
Preference Stock, $1 par value [Member]
Redeemable Preferred and Preference Stock:
Preferred and preference stock of subsidiaries	343,000,000	343,000,000
Preference Stock , $100 par or stated value [Member]
Redeemable Preferred and Preference Stock:
Preferred and preference stock of subsidiaries	368,000,000	368,000,000
Noncontrolling Interest [Member]
Redeemable Preferred and Preference Stock:
Preferred and preference stock of subsidiaries	221,000,000	0
Adjustable Rate Loans [Member]
Maturity
Long-term Debt, Maturities, Repayments of Principal in Next Twelve Months	0	11,000,000
Long-term debt maturities, 2016	775,000,000	525,000,000
Long-term Debt, Maturities, Repayments of Principal in Year Three	450,000,000	450,000,000
Affiliate trusts, variable rate, due 2042 [Member]
Maturity
Total long term debt payable to affiliated trusts	206,000,000	206,000,000
Long-term senior notes and debt:
Fixed stated interest rate of debt obligation	3.36%
Pollution control revenue bonds due 2019 [Member]
Pollution control revenue bonds --
Long-term pollution control bonds	25,000,000	25,000,000
Pollution control revenue bonds due 2022 through 2049 [Member]
Pollution control revenue bonds --
Long-term pollution control bonds	1,466,000,000	1,453,000,000
Pollution control revenue bonds variable rate, Due 2015 [Member]
Pollution control revenue bonds --
Long-term pollution control bonds	152,000,000	54,000,000
Pollution control revenue bonds variable rate, Due 2016 [Member]
Long-term senior notes and debt:
Fixed stated interest rate of debt obligation	0.04%
Pollution control revenue bonds --
Long-term pollution control bonds	4,000,000	4,000,000
Pollution control revenue bonds variable rate, Due 2017 [Member]
Pollution control revenue bonds --
Long-term pollution control bonds	36,000,000	36,000,000
Pollution control revenue bonds variable rate, Due 2018 [Member]
Long-term senior notes and debt:
Fixed stated interest rate of debt obligation		0.04%
Pollution control revenue bonds --
Long-term pollution control bonds	0	19,000,000
Plant Daniel revenue bonds due 2021 [Member]
Long-term senior notes and debt:
Fixed stated interest rate of debt obligation	7.13%	7.13%
Pollution control revenue bonds --
Taxable Revenue Bonds	270,000,000	270,000,000
Pollution control revenue bonds variable rate, Due 2020 to 2052 [Member]
Pollution control revenue bonds --
Long-term pollution control bonds	1,566,000,000	1,642,000,000
Loan For Federal Financing Bank	1,200,000,000	0
Alabama Power [Member]
Maturity
Total long term debt payable to affiliated trusts	206,000,000	206,000,000
Long-term Debt, Maturities, Repayments of Principal in Next Twelve Months	400,000,000	400,000,000
Long-term debt maturities, 2016	200,000,000	200,000,000
Long-term Debt, Maturities, Repayments of Principal in Year Three	525,000,000	525,000,000
Long-term Debt, Maturities, Repayments of Principal in Year Five	200,000,000	200,000,000
Long-term debt maturities, thereafter	3,950,000,000	3,550,000,000
Long-term senior notes and debt:
Total long-term notes payable	5,275,000,000	4,875,000,000
Pollution control revenue bonds --
Long-term pollution control bonds	1,200,000,000	1,200,000,000
Total other long -term debt	1,151,000,000	1,151,000,000
Capitalized lease obligations	5,000,000	5,000,000
Unamortized debt (discount), net	(7,000,000)	(4,000,000)
Total long-term debt (annual interest requirement )	6,630,000,000	6,233,000,000
Less amount due within one year	454,000,000	0
Long-term debt excluding amount due within one year	6,176,000,000	6,233,000,000
Percent capitalization	49.00%	50.20%
Redeemable Preferred and Preference Stock:
Redeemable preferred stock	342,000,000	342,000,000
Total redeemable preferred stock - percent capitalization	2.70%	2.70%
Preference stock	343,000,000	343,000,000
Preferred stock	342,000,000	342,000,000
Total preferred and preference stock of subsidiaries - percent capitalization	2.70%	2.80%
Common Stockholders' Equity:
Common stock	1,222,000,000	1,222,000,000
Paid-in capital	2,304,000,000	2,262,000,000
Retained earnings	2,255,000,000	2,044,000,000
Accumulated other comprehensive loss	(29,000,000)	(26,000,000)
Total Common Stockholders' Equity	5,752,000,000	5,502,000,000
Total common stockholders' equity - percent capitalization	45.60%	44.30%
Total stockholders' equity	5,752,000,000	5,502,000,000
Total Capitalization	12,613,000,000	12,420,000,000
Percent Capitalization	100.00%	100.00%
Alabama Power [Member] \| Redeemable Preferred Stock, $100 par or stated value [Member] \| Cumulative Preferred Stock [Member]
Redeemable Preferred and Preference Stock:
Redeemable preferred stock	48,000,000	48,000,000
Alabama Power [Member] \| Redeemable Preferred Stock, $1 par value [Member] \| Cumulative Preferred Stock [Member]
Redeemable Preferred and Preference Stock:
Redeemable preferred stock	294,000,000	294,000,000
Alabama Power [Member] \| Affiliate trusts, variable rate, due 2042 [Member]
Long-term senior notes and debt:
Fixed stated interest rate of debt obligation	3.36%
Alabama Power [Member] \| Pollution control revenue bonds due 2034 [Member]
Pollution control revenue bonds --
Long-term pollution control bonds	367,000,000	367,000,000
Alabama Power [Member] \| Pollution control revenue bonds due 2015 [Member]
Long-term senior notes and debt:
Fixed stated interest rate of debt obligation	0.03%
Pollution control revenue bonds --
Long-term pollution control bonds	54,000,000	54,000,000
Alabama Power [Member] \| Pollution control revenue bonds variable rate, Due 2017 [Member]
Pollution control revenue bonds --
Long-term pollution control bonds	36,000,000	36,000,000
Alabama Power [Member] \| Pollution control revenue bonds due 2021-2038 [Member]
Pollution control revenue bonds --
Long-term pollution control bonds	694,000,000	694,000,000
Georgia Power [Member]
Maturity
Long-term Debt, Maturities, Repayments of Principal in Next Twelve Months	1,050,000,000	1,050,000,000
Long-term debt maturities, 2016	250,000,000	250,000,000
Long-term Debt, Maturities, Repayments of Principal in Year Three	450,000,000	450,000,000
Long-term Debt, Maturities, Repayments of Principal in Year Four	250,000,000	250,000,000
Long-term Debt, Maturities, Repayments of Principal in Year Five	500,000,000	500,000,000
Long-term debt maturities, thereafter	3,975,000,000	3,975,000,000
Long-term senior notes and debt:
Long Term Debt Maturities Repayments of Principal Variable in Year Four	450,000,000	450,000,000
Total long-term notes payable	6,925,000,000	6,925,000,000
Pollution control revenue bonds --
Long-term pollution control bonds	1,600,000,000	1,700,000,000
Loan For Federal Financing Bank	1,200,000,000	0
Total other long -term debt	2,883,000,000	1,680,000,000
Capitalized lease obligations	40,000,000	45,000,000
Unamortized debt (discount), net	(11,000,000)	(12,000,000)
Total long-term debt (annual interest requirement )	9,837,000,000	8,638,000,000
Less amount due within one year	1,154,000,000	5,000,000
Long-term debt excluding amount due within one year	8,683,000,000	8,633,000,000
Percent capitalization	44.80%	46.70%
Redeemable Preferred and Preference Stock:
Preference stock	221,000,000	221,000,000
Preferred stock	45,000,000	45,000,000
Total preferred and preference stock of subsidiaries - percent capitalization	1.40%	1.40%
Common Stockholders' Equity:
Common stock	398,000,000	398,000,000
Paid-in capital	6,196,000,000	5,633,000,000
Retained earnings	3,835,000,000	3,565,000,000
Accumulated other comprehensive loss	(8,000,000)	(5,000,000)
Total Common Stockholders' Equity	10,421,000,000	9,591,000,000
Total common stockholders' equity - percent capitalization	53.80%	51.90%
Total stockholders' equity	10,421,000,000	9,591,000,000
Total Capitalization	19,370,000,000	18,490,000,000
Percent Capitalization	100.00%	100.00%
Georgia Power [Member] \| Noncumulative Preferred Stock, $25 par value [Member]
Redeemable Preferred and Preference Stock:
Preferred stock	45,000,000	45,000,000
Georgia Power [Member] \| Noncumulative Preferred Stock, $100 par value [Member]
Redeemable Preferred and Preference Stock:
Preference stock	221,000,000	221,000,000
Georgia Power [Member] \| Noncumulative Preferred Stock [Member]
Redeemable Preferred and Preference Stock:
Total preferred and preference stock	266,000,000	266,000,000
Georgia Power [Member] \| Pollution control revenue bonds due 2022 - 2049 [Member]
Pollution control revenue bonds --
Long-term pollution control bonds	818,000,000	818,000,000
Georgia Power [Member] \| Pollution control revenue bonds variable rate, Due 2015 [Member]
Pollution control revenue bonds --
Long-term pollution control bonds	98,000,000	0
Georgia Power [Member] \| Pollution control revenue bonds variable rate, Due 2016 [Member]
Long-term senior notes and debt:
Fixed stated interest rate of debt obligation	0.04%
Pollution control revenue bonds --
Long-term pollution control bonds	4,000,000	4,000,000
Georgia Power [Member] \| Pollution control revenue bonds variable rate, Due 2018 [Member]
Long-term senior notes and debt:
Fixed stated interest rate of debt obligation		0.04%
Pollution control revenue bonds --
Long-term pollution control bonds	0	20,000,000
Georgia Power [Member] \| Pollution control revenue bonds due 2022-2052 [Member]
Pollution control revenue bonds --
Long-term pollution control bonds	763,000,000	838,000,000
Gulf Power [Member]
Maturity
Long-term Debt, Maturities, Repayments of Principal in Next Twelve Months	0	75,000,000
Long-term Debt, Maturities, Repayments of Principal in Year Three	110,000,000	110,000,000
Long-term Debt, Maturities, Repayments of Principal in Year Four	85,000,000	85,000,000
Long-term debt maturities, thereafter	875,000,000	675,000,000
Long-term senior notes and debt:
Total long-term notes payable	1,070,000,000	945,000,000
Pollution control revenue bonds --
Long-term pollution control bonds	309,000,000	296,000,000
Total other long -term debt	308,955,000	295,955,000
Unamortized debt (discount), net	(9,361,000)	(7,792,000)
Total long-term debt (annual interest requirement )	1,369,594,000	1,233,163,000
Less amount due within one year	0	75,000,000
Long-term debt excluding amount due within one year	1,369,594,000	1,158,163,000
Percent capitalization	48.50%	45.60%
Redeemable Preferred and Preference Stock:
Total redeemable preferred stock - percent capitalization	5.20%	5.80%
Preference stock	146,504,000	146,504,000
Common Stockholders' Equity:
Common stock	483,060,000	433,060,000
Paid-in capital	559,797,000	552,681,000
Retained earnings	267,470,000	250,494,000
Accumulated other comprehensive loss	(737,000)	(1,109,000)
Total Common Stockholders' Equity	1,309,590,000	1,235,126,000
Total common stockholders' equity - percent capitalization	46.30%	48.60%
Total stockholders' equity	1,309,590,000	1,235,126,000
Total Capitalization	2,825,688,000	2,539,793,000
Percent Capitalization	100.00%	100.00%
Gulf Power [Member] \| 6% Preference stock [Member]
Redeemable Preferred and Preference Stock:
Preference stock	53,886,000	53,886,000
Gulf Power [Member] \| 6.45 % Preference stock [Member]
Redeemable Preferred and Preference Stock:
Preference stock	44,112,000	44,112,000
Gulf Power [Member] \| Five Point Six Percentage Hundred Dollar Par or Stated Value [Member]
Redeemable Preferred and Preference Stock:
Preference stock	48,506,000	48,506,000
Gulf Power [Member] \| Pollution control revenue bonds due 2022 - 2049 [Member]
Pollution control revenue bonds --
Long-term pollution control bonds	239,625,000	226,625,000
Gulf Power [Member] \| Pollution control revenue bonds due 2022-2039 [Member]
Pollution control revenue bonds --
Long-term pollution control bonds	69,330,000	69,330,000
Mississippi Power [Member]
Maturity
Long-term debt maturities, 2016	300,000,000	300,000,000
Long-term Debt, Maturities, Repayments of Principal in Year Three	35,000,000	35,000,000
Long-term Debt, Maturities, Repayments of Principal in Year Four	125,000,000	125,000,000
Long-term debt maturities, thereafter	680,000,000	680,000,000
Long-term senior notes and debt:
Fixed stated interest rate of debt obligation	10.134%	9.932%
Adjustable, 2014	0	11,250,000
Long Term Debt Maturities Repayments of Principal Adjustable in Year Two	775,000,000	525,000,000
Total long-term notes payable	1,915,000,000	1,676,250,000
Pollution control revenue bonds --
Long-term pollution control bonds	82,700,000	82,700,000
Taxable Revenue Bonds		11,300,000
Total other long -term debt	352,695,000	352,695,000
Capitalized lease obligations	79,679,000	82,217,000
Unamortized debt premium (related to plant acquisition)	62,701,000	71,807,000
Unamortized debt discount	(1,921,000)	(2,113,000)
Total long-term debt (annual interest requirement )	2,408,154,000	2,180,856,000
Less amount due within one year	777,667,000	13,789,000
Long-term debt excluding amount due within one year	1,630,487,000	2,167,067,000
Percent capitalization	43.50%	49.60%
Redeemable Preferred and Preference Stock:
Total redeemable preferred stock - percent capitalization	0.90%	0.70%
Preferred stock	32,780,000	32,780,000
Common Stockholders' Equity:
Common stock	37,691,000	37,691,000
Paid-in capital	2,612,136,000	2,376,595,000
Retained earnings	(558,552,000)	(229,871,000)
Accumulated other comprehensive loss	(7,015,000)	(7,864,000)
Total Common Stockholders' Equity	2,084,260,000	2,176,551,000
Total common stockholders' equity - percent capitalization	55.60%	49.70%
Total stockholders' equity	2,084,260,000	2,176,551,000
Total Capitalization	3,747,527,000	4,376,398,000
Percent Capitalization	100.00%	100.00%
Mississippi Power [Member] \| Pollution control revenue bonds due 2028 [Member]
Pollution control revenue bonds --
Long-term pollution control bonds	42,625,000	42,625,000
Mississippi Power [Member] \| Pollution control revenue bonds due 2020-2028 [Member]
Pollution control revenue bonds --
Long-term pollution control bonds	40,070,000	40,070,000
Mississippi Power [Member] \| Plant Daniel revenue bonds due 2021 [Member]
Long-term senior notes and debt:
Fixed stated interest rate of debt obligation	7.13%	7.13%
Pollution control revenue bonds --
Taxable Revenue Bonds	$ 270,000,000	$ 270,000,000

Capitalization in percent.

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As a percent of total capitalization, the total of all Common Stockholders' Equity (deficit) items, net of receivables from officers, directors owners, and affiliates of the entity. This excludes temporary equity and preferred and preference stockholders' equity.

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Loan For Federal Financing Bank

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Sum of the carrying values as of the balance sheet date of all long-term debt, which is debt initially having maturities due after one year from the balance sheet date or beyond the operating cycle, if longer, plus capital lease obligations.

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As a percent of total capitalization, the sum of the carrying values as of the balance sheet date of all long-term debt, which is debt initially having maturities due after one year from the balance sheet date or beyond the operating cycle, if longer, but excluding the portions thereof scheduled to be repaid within one year or the normal operating cycle, if longer plus capital lease obligations due to be paid more than one year after the balance sheet date.

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Long term debt maturities repayments of principal adjustable in next twelve months.

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Long Term Debt Maturities Repayments of Principal Adjustable in Year Two

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Amount of long-term debt matured in the past twelve months following the date of the latest balance sheet presented in the financial statements, which may include maturities of long term debt, sinking fund requirements, and other securities redeemable at fixed or determinable prices and dates.

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Long Term Debt Maturities Repayments of Principal Variable in Year Four

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Including the current and noncurrent portions, carrying value as of the balance sheet date of Long-term Notes and Other Long-term Debt with the highest claim on the assets of the issuer in case of bankruptcy or liquidation (with maturities initially due after one year or beyond the operating cycle if longer). Senior note holders are paid off in full before any payments are made to junior note holders.

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As a percent of total capitalization, the total of all Stockholders' Equity (deficit) items, net of receivables from officers, directors owners, and affiliates of the entity which is directly or indirectly attributable to that ownership interest in subsidiary equity which is not attributable to the parent (noncontrolling interest, minority interest).

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Value of all nonredeemable preference stock (or preference stock redeemable solely at the option of the issuer) held by shareholders, which is net of related treasury stock. May be all or a portion of the number of preference shares authorized. These shares represent the ownership interest of the preference shareholders.

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Redeemable And Preference Stock.

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Taxable Revenue Bonds

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As a percent of total capitalization, the carrying value (book value) of an entity's issued and outstanding stock which is not included within permanent equity in Stockholders Equity. Temporary equity is a security with redemption features that are outside the control of the issuer, is not classified as an asset or liability in conformity with GAAP, and is not mandatorily redeemable. Includes any type of security that is redeemable at a fixed or determinable price or on a fixed or determinable date or dates, is redeemable at the option of the holder, or has conditions for redemption which are not solely within the control of the issuer. If convertible, the issuer does not control the actions or events necessary to issue the maximum number of shares that could be required to be delivered under the conversion option if the holder exercises the option to convert the stock to another class of equity. If the security is a warrant or a rights issue, the warrant or rights issue is considered to be temporary equity if the issuer cannot demonstrate that it would be able to deliver upon the exercise of the option by the holder in all cases. Includes stock with a put option held by an ESOP and stock redeemable by a holder only in the event of a change in control of the issuer.

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Value received from shareholders in common stock-related transactions that are in excess of par value or stated value and amounts received from other stock-related transactions. Includes only common stock transactions (excludes preferred stock transactions). May be called contributed capital, capital in excess of par, capital surplus, or paid-in capital.

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This element represents the total consolidated (as applicable) capitalization of the entity which is comprised of its long-term debt and equity instruments. The table may be detailed by subsidiary (legal entity) and include information by type of debt or equity detailed by instrument.

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Carrying value as of the balance sheet date of notes payable (with maturities initially due after one year or beyond the operating cycle if longer), excluding current portion.

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Amount of stockholders' equity (deficit), net of receivables from officers, directors, owners, and affiliates of the entity, attributable to both the parent and noncontrolling interests. Amount excludes temporary equity. Alternate caption for the concept is permanent equity.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 810

-SubTopic 10

-Section 45

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Carrying amount, attributable to parent, of an entity's issued and outstanding stock which is not included within permanent equity. Temporary equity is a security with redemption features that are outside the control of the issuer, is not classified as an asset or liability in conformity with GAAP, and is not mandatorily redeemable. Includes any type of security that is redeemable at a fixed or determinable price or on a fixed or determinable date or dates, is redeemable at the option of the holder, or has conditions for redemption which are not solely within the control of the issuer. Includes stock with a put option held by an ESOP and stock redeemable by a holder only in the event of a change in control of the issuer.

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No definition available.

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The amount allocated to treasury stock. Treasury stock is common and preferred shares of an entity that were issued, repurchased by the entity, and are held in its treasury.

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-Topic 505

-SubTopic 30

-Section 50

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