Financial reporting - balance sheet - assets - accruals accounting.
Accrued income is revenue earned by a business but not yet invoiced or received from the customer.
It is an asset.
(The related accounting entries being: DEBIT Accrued income in the balance sheet; and CREDIT Revenue in the income statement.)
Future economic benefits are expected to flow from the asset to the reporting entity.
Namely the future cash receipt from the customer.
There is no liability associated with this asset, because we have already undertaken the relevant revenue-earning work.
For this reason, the revenue is recognised already, in the income statement.