COMMITMENTS AND CONTINGENCIES - Cardholders (Details) $ in Millions	Dec. 31, 2019 USD ($)
AIR MILES Reward Program
Letters of credit and other assurances	$ 141.7

Represents the aggregate of letters of credit and other assurances at the balance sheet date obtained from certain AIR MILES Reward Program sponsors.

No definition available.

Name:	ads_LettersOfCreditAndOtherAssurances
Namespace Prefix:	ads_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant