SCHEDULE 13G  
  
Amendment No. 1  
First Bank System Incorporated  
Common Stock  
Cusip # 319279105  
 
 
Cusip # 319279105  
Item 1:	Reporting Person - FMR Corp.  
Item 4:	Commonwealth of Massachusetts  
Item 5:	None  
Item 6:	None  
Item 7:	None  
Item 8:	None  
Item 9:	None  
Item 11:	0.00%  
Item 12:	HC   
  
  
 
 
Cusip # 319279105  
Item 1:	Reporting Person - Edward C. Johnson 3d   
Item 4:	United States of America  
Item 5:	None  
Item 6:	None  
Item 7:	None  
Item 8:	None  
Item 9:	None  
Item 11:	0.00%  
Item 12:	IN   
  
 
 
Cusip # 319279105  
Item 1:	Reporting Person - Abigail P. Johnson   
Item 4:	United States of America  
Item 5:	None  
Item 6:	None  
Item 7:	None  
Item 8:	None  
Item 9:	None  
Item 11:	0.00%  
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:  
  
		First Bank System Incorporated  
  
Item 1(b).	Name of Issuer's Principal Executive Offices:  
  
		First Bank Pl, 601 Second Ave S  
		Minneapolis, MN  55402-4302  
  
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:    
  
		319279105  
  
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: 
	None  
  
	(b)	Percent of Class: 
	0.00%  
  
	(c)	Number of shares as to which such person has:    
  
	(i)	sole power to vote or to direct the vote: 
	None  
  
	(ii)	shared power to vote or to direct the vote: 
	None  
  
	(iii)	sole power to dispose or to direct the disposition of: 
	None  
  
	(iv)	shared power to dispose or to direct the disposition of: 
	None  
  
  
 
 
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 any 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 any 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 First Bank System Incorporated  
at December 31, 1997 is true, complete and correct.   
  
  
	February 14, 1998	  
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