Employee Benefit Plans - Schedule of Nonvested Restricted Stock Units Activity (Details) - RSUs - $ / shares		3 Months Ended
	Jan. 03, 2022	Mar. 31, 2022
Number of Shares
Beginning balance (in shares)		0
Unvested CIT RSUs converted to BancShares RSUs at Merger Date (in shares)		116,958,000,000
Unvested PSUs converted to RSUs at merger date (in shares)	10,678,000,000
Forfeited / cancelled (in shares)		(411,000,000)
Ending balance (in shares)		55,959,000,000
Weighted Average Grant Date Value
Beginning balance (in dollars per share)		$ 0
Unvested CIT RSUs converted to BancShares RSUs at Merger Date (in dollars per share)		859.76
Unvested CIT PSUs converted to RSUs at Merger Date (in dollars per share)	$ 859.76
Forfeited / cancelled (in dollars per share)		859.76
Ending balance (in dollars per share)		$ 859.76
Restricted Stock Unit, Settled Awards
Number of Shares
Vested (in shares)		(71,171,000,000)
Weighted Average Grant Date Value
Vested (in dollars per share)		$ 859.76
Restricted Stock Unit, Unsettled Awards
Number of Shares
Vested (in shares)		(95,000,000)
Weighted Average Grant Date Value
Vested (in dollars per share)		$ 859.76