brotherton-erpnext/erpnext/public/js/payment/payment_details.html

<div class="row pos-payment-row" type="{{type}}" idx={{idx}}>
    <div class="col-xs-6">{{mode_of_payment}}</div>
	<div class="col-xs-6">
		<div class="input-group">
			<input disabled class="form-control text-right amount" idx="{{idx}}" type="text" value="{{format_number(amount, 2)}}">
			<span class="input-group-btn">
				<button type="button" class="btn btn-default clr" idx="{{idx}}" style="border:1px solid #d1d8dd">C</button>
			</span>
		</div>
	</div>
</div>