The seizure included Rs 10 crore in scrapped denomination of Rs 500, and Rs 10 lakh in 2,000 rupee banknotes, a senior official said.
Officers of Tilaknagar police station found the notes stuffed in two gunny bags after they flagged down the car this evening.
The detainees claimed to have been employed with a cooperative bank in Pune district.
"One of them is the manager in Pimpri Chinchwad branch of the Vaidyanath Urban Cooperative Bank and told the police the cash belonged to the bank, while other two claimed they are also employees of the bank," Shahaji Umap, DCP (Zone VI) said, adding "the police are verifying the record."
"We are verifying their claim and will seek help from the Income Tax Department," Mumbai police spokesperson and DCP Ashok Dudhe said.