title: Calculating subtotals in pandas pivot_table with MultiIndex
body: <p>I have the following raw data, in a dataframe:</p>
  <pre><code>   BROKER    VENUE  QUANTITY
  0  BrokerA  Venue_1       300
  1  BrokerA  Venue_2       400
  2  BrokerA  Venue_2      1400
  3  BrokerA  Venue_3       800
  4  BrokerB  Venue_2       500
  5  BrokerB  Venue_3      1100
  6  BrokerC  Venue_1      1000
  7  BrokerC  Venue_1      1200
  8  BrokerC  Venue_2     17000
  </code></pre>
  <p>I want to do some summarization of the data to see how much each broker sent to each venue, so I created a pivot_table:</p>
  <pre><code>pt = df.pivot_table(index=['BROKER', 'VENUE'], values=['QUANTITY'], aggfunc=np.sum)
  </code></pre>
  <p>Result, as expected:</p>
  <pre><code>                 QUANTITY
  BROKER  VENUE            
  BrokerA Venue_1     300.0
          Venue_2    1800.0
          Venue_3     800.0
  BrokerB Venue_2     500.0
          Venue_3    1100.0
  BrokerC Venue_1    2200.0
          Venue_2   17000.0
  </code></pre>
  <p>I also want how much was sent by each broker overall. and show it in this same table. I can get that information by typing <code>df.groupby('BROKER').sum()</code>, but how can I add this to my pivot table as a column named, say, BROKER_TOTAL?</p>
  <p>Note: This question is similar but seems to be on an older version, and my best guess at adapting it to my situation didn't work: <a href="https://stackoverflow.com/questions/15570099/pandas-pivot-tables-row-subtotals">Pandas Pivot tables row subtotals</a></p>