Contract Receivables, Net - Summary of Reconciliation of Billed Contract Receivables Sold to MUF Including Receivables Sold to MUFC And Collected from Customers on Behalf of MUFG And Receivables Not Yet Collected from Customers (Parenthetical) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024
Receivables [Abstract]
Proceeds from (Payments for) Sale of Billed Contract Receivables	$ 12.2	$ 4.7