SCHEDULE 13G

Amendment No. 1
Capstead Mortgage Corporation
Common Stock
Cusip #14067E506


Cusip #14067E506
Item 1:	Reporting Person - FMR Corp.
Item 4:	Commonwealth of Massachusetts
Item 5:	0
Item 6:	0
Item 7:	0
Item 8:	0
Item 9:	0
Item 11:	0.000%
Item 12:	    HC


Cusip #14067E506
Item 1:	Reporting Person - Edward C. Johnson 3d
Item 4:	United States of America
Item 5:	0
Item 6:	0
Item 7:	0
Item 8:	0
Item 9:	0
Item 11:	0.000%
Item 12:	IN


Cusip #14067E506
Item 1:	Reporting Person - Abigail P. Johnson
Item 4:	United States of America
Item 5:	None
Item 6:	None
Item 7:	0
Item 8:	None
Item 9:	0
Item 11:	0.000%
Item 12:	    IN



SCHEDULE 13G - TO BE INCLUDED IN STATEMENTS
FILED PURSUANT TO RULE 13d-1(b) or 13d-2(b)


Item 1(a).	Name of Issuer:

		Capstead Mortgage Corporation

Item 1(b).	Name of Issuer's Principal Executive Offices:

		8401 North Central Expressway, Suite
800
		Dallas, TX  75225

Item 2(a).	Name of Person Filing:

		FMR Corp.

Item 2(b).	Address or Principal Business Office or, if None,
Residence:

		82 Devonshire Street, Boston,
Massachusetts  02109

Item 2(c).	Citizenship:

		Not applicable

Item 2(d).	Title of Class of Securities:

		Common Stock

Item 2(e).	CUSIP Number:

		14067E506

Item 3.	This statement is filed pursuant to Rule 13d-1(b) or 13d-2(b)
and the person filing, FMR Corp., is a parent holding company
in accordance with Section 240.13d-1(b)(ii)(G).  (Note:  See
Item 7).

Item 4.	Ownership

	(a)	Amount Beneficially Owned:	0

	(b)	Percent of Class:	0.000%

	(c)	Number of shares as to which such
person has:

	(i)	sole power to vote or to direct
the vote:	0

	(ii)	shared power to vote or to
direct the vote:	0

	(iii)	sole power to dispose or to
direct the disposition of:	0

	(iv)	shared power to dispose or to
direct the disposition of:	0



Item 5.	Ownership of Five Percent or Less of a Class.

	If this statement is being filed to report the fact that as of the
date hereof, the reporting person has ceased to be the
beneficial owner of more than five percent of the class of
securities, check the following (X).

Item 6.	Ownership of More than Five Percent on Behalf of Another
Person.

	Not applicable

Item 7.	Identification and Classification of the Subsidiary Which
Acquired the Security Being Reported on By the Parent
Holding Company.

	Not applicable

Item 8.	Identification and Classification of Members of
the Group.

	Not Applicable

Item 9.	Notice of Dissolution of Group.

	Not applicable.

Item 10.	Certification.

	Inasmuch as the reporting persons are no longer the beneficial
owners of more than five percent of the number of shares
outstanding, the reporting persons have no further reporting
obligation under Section 13(d) of the Securities and Exchange
Commission thereunder, and the reporting persons have no
obligation to amend this Statement if any material change
occurs in the facts set forth herein.

Signature

	After reasonable inquiry and to the best of my knowledge and
belief, I certify that the information set forth in this Schedule
13G in connection with FMR Corp.'s beneficial ownership of
the Common Stock of Capstead Mortgage Corporation at
August 31, 2001 is true, complete and correct.

September 10, 2001
Date

/s/Eric D. Roiter
Signature

Eric D. Roiter
Duly authorized under Power of Attorney
dated December 30, 1997 by and on behalf
of FMR Corp. and its direct and indirect
subsidiaries