ABC Construction Company has been awarded a $20 million contract to build a bridge. The project will commence on 1 January 2017 and has an expected completion date of 31 December 2019. ABC Construction Company uses the percentage-of-completion method to recognise profit. The end of the financial year is 31 December. The following data relates to the project: (amounts in millions) 2017 2018 2019 Costs incurred to date 3 8 16 Estimated total costs 15 16 16 Billings 2.5 4 13.5 Receipts 2 3 15 As at 31 December 2018, how much payment has ABC Construction collected from the customer?