Table:
Combined Pension Plan

Years Ended December 31,

2019	2018	2017

(Dollars in millions)

Change in benefit obligation

Benefit obligation at beginning of year	$11,594	13,064	13,244

Service cost	56	66	63

Interest cost	436	392	409

Plan amendments	(9)	—	—

Special termination benefits charge	6	15	—

Actuarial (gain) loss	1,249	(765)	586

Benefits paid from plan assets	(1,115)	(1,178)	(1,238)

Benefit obligation at end of year	$12,217	11,594	13,064

Read the shown table in this image and give me the reconstructed table in the HTML format, presented as plain text.

<table border='1' cellspacing='0'>
<tr> <th>  </th> <th>  </th> <th> Combined Pension Plan </th> <th>  </th> </tr>
<tr> <td>  </td> <td>  </td> <td> Years Ended December 31, </td> <td>  </td> </tr>
<tr> <td>  </td> <td> 2019 </td> <td> 2018 </td> <td> 2017 </td> </tr>
<tr> <td>  </td> <td>  </td> <td> (Dollars in millions) </td> <td>  </td> </tr>
<tr> <td> Change in benefit obligation </td> <td>  </td> <td>  </td> <td>  </td> </tr>
<tr> <td> Benefit obligation at beginning of year </td> <td> $11,594 </td> <td> 13,064 </td> <td> 13,244 </td> </tr>
<tr> <td> Service cost </td> <td> 56 </td> <td> 66 </td> <td> 63 </td> </tr>
<tr> <td> Interest cost </td> <td> 436 </td> <td> 392 </td> <td> 409 </td> </tr>
<tr> <td> Plan amendments </td> <td> (9) </td> <td> — </td> <td> — </td> </tr>
<tr> <td> Special termination benefits charge </td> <td> 6 </td> <td> 15 </td> <td> — </td> </tr>
<tr> <td> Actuarial (gain) loss </td> <td> 1,249 </td> <td> (765) </td> <td> 586 </td> </tr>
<tr> <td> Benefits paid from plan assets </td> <td> (1,115) </td> <td> (1,178) </td> <td> (1,238) </td> </tr>
<tr> <td> Benefit obligation at end of year </td> <td> $12,217 </td> <td> 11,594 </td> <td> 13,064 </td> </tr>
</table>