How to display the total discount amount on my shopping cart?

Question

How can I display the total discount amount on my shopping cart?

I can get the subtotal and grandtotal from the code below, but what about the total discount?

$quote = Mage::getSingleton('checkout/cart')->getQuote();
$grandTotal = $quote->getGrandTotal();
$subTotal =  $quote->getSubtotal();
var_dump($subTotal);

What I need,

Subtotal           €220
Discount           €20
TOTAL AMOUNT       €200

What from Magento,

Subtotal           €200 // should be €220
Discount           
TOTAL AMOUNT       €200

I'm using Magento 1.8