如何从txt文件中删除奇怪的编码

我正在尝试处理这样的文本文件：

http://www.sec.gov/Archives/edgar/data/789019/000119312514289961/0001193125-14-289961.txt

如果您在文件中间看到，则如下所示：

</TEXT>
</DOCUMENT>
<DOCUMENT>
<TYPE>EXCEL
<SEQUENCE>21
<FILENAME>Financial_Report.xlsx
<DESCRIPTION>IDEA: XBRL DOCUMENT
<TEXT>
begin 644 Financial_Report.xlsx
M4$L#!!0`!@`(````(0!):[_C#0,``+!)```3``@"6T-O;G1E;G1?5'EP97-=
M+GAM;""B!`(HH``"````````````````````````````````````````````
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M``````````````````````````````````````#,W,M.VT`4QO%]I;Z#Y6V5
M>([OK@@L>EFV2*4/,+4GQ,(W>08*;]^)N0BA%(2*U/^&B,2>\\6+G[+YSM')
M==\%5V:V[3AL0EFK,#!#/3;M<+X)?YY]795A8)T>&MV-@]F$-\:&)\?OWQV=
MW4S&!O[NP6["G7/3QRBR]<[TVJ['R0S^D^TX]]KY?^?S:-+UA3XW4:Q4'M7C
MX,S@5FY_1GA\]-EL]67G@B_7_NW;)+/I;!A\NKUP/VL3ZFGJVEH[GS2Z&IHG
M4U9W$];^SN4:NVLG^\''"*.#$_:?_'W`W7W?_:.9V\8$IWIVWW3O8T377?1[
MG"]^C>/%^OE##J0<M]NV-LU87_;^":SM-!O=V)TQKN_6R^NZU^UPG_N9^<O%
M-EI>Y(V#[+_?<O`K<\20'`DD1PK)D4%RY)`<!21'"<E107*(H@2AB"H44H5B
MJE!0%8JJ0F%5**X*!5:AR!I39(TILL8466.*K#%%UI@B:TR1-:;(&E-DC2FR
M)A19$XJL"476A")K0I$UH<B:4&1-*+(F%%D3BJPI1=:4(FM*D36ER)I29$TI
MLJ8465.*K"E%UI0B:T:1-:/(FE%DS2BR9A19,XJL&476C")K1I$UH\B:4V3-
M*;+F%%ESBJPY1=:<(FM.D36GR)I39,TILA8460N*K`5%UH(B:T&1M:#(6E!D
M+2BR%A19"XJL)476DB)K29&UI,A:4F0M*;*6%%E+BJPE1=:2(FM%D;6BR%I1
M9*THLE8462N*K!5%UHHB:T61M:+(*HI"JRB*K:(HN(JBZ"J*PJLHBJ^B*,"*
MH@@KBD*L*(RQH#H6QEA.(8O3R.)4LCB=+$XIB]/*XM2R,+TLP12S!-/,$DPU
M2S#=+,&4LP33SA),/4LP_2S!%+0$T]"2_U;1<GX?CHF6O__^`W8YYH6%+-;=
M=,:^\1*%VT-?FKS3LVE^N-EO#GKS`(_/?BZ'WZMS.H^3]1N&9O/ZIW"_0FA_
M]VKR!YG9M>9AB="A93P/$_UVHM</?+(-R.SW'S6F.3`[6O8M'?\!``#__P,`
M4$L#!!0`!@`(````(0"U53`C]0```$P"```+``@"7W)E;',O+G)E;',@H@0"

这似乎是一个excel文件吗？还是XBRL文档？那是什么 ？我如何摆脱它（或以某种方式“处理”它？）这种情况持续了数千行，所以我想它是某些附件的某些链接的某种编码？知道如何处理吗？

我正在尝试在Python中使用BeautifulSoup：

from bs4 import BeautifulSoup

with open("textWithHtml.txt") as markup:
    soup = BeautifulSoup(markup.read())

with open("processedText.txt", "w") as f: 
    f.write(soup.get_text().encode('utf-8'))

但并非所有内容都被删除，而且我注意到在某些情况下甚至没有删除所有html标记。有时运行两次代码会比第一次运行BeautifulSoup代码时删除的内容多。