If you have changed your username and/or password, then this applies to all your accounts.

It applies to all your Capital One® accounts, including a checking or savings account (opened at a branch or online), a credit card, investment account, home or car loan. Once you make the switch, you can use the same username and password to sign in to all your accounts.

There are two exceptions – if you have a business account with Capital One Credit Card and/or Capital One Bank, you'll need to keep separate sign in info for that account.