Mortgage Servicing Assets (Tables)

3 Months Ended

Mar. 31, 2022

Servicing Asset [Abstract]

Changes in Carrying Amount of Mortgage Servicing Assets

Changes in the carrying amount of commercial mortgage servicing assets are summarized as follows:

	Three months ended March 31,
Dollars in millions	2022		2021
Balance at beginning of period	$	634	$	578
Servicing retained from loan sales	30		29
Purchases	11		7
Amortization	(31)		(29)
Temporary (impairments) recoveries	—		3
Balance at end of period	$	644	$	588
Fair value at end of period	$	846	$	682

Changes in the carrying amount of residential mortgage servicing assets are summarized as follows:

	Three months ended March 31,
Dollars in millions	2022		2021
Balance at beginning of period	$	93	$	58
Servicing retained from loan sales	11		11
Purchases	—		—
Amortization	(4)		(5)
Temporary (impairments) recoveries	1		8
Balance at end of period	$	101	$	72
Fair value at end of period	$	116	$	77

Schedule of Range and Weighted-Average of Significant Unobservable Inputs

The range and weighted average of the significant unobservable inputs used to determine the fair value of our commercial mortgage servicing assets at March 31, 2022, and March 31, 2021, along with the valuation techniques, are shown in the following table: 

dollars in millions		March 31, 2022						March 31, 2021
Valuation Technique	Significant Unobservable Input	Range				Weighted Average		Range				Weighted Average
Discounted cash flow	Expected defaults	1.00	%	2.00	%	1.12	%	1.01	%	2.00	%	1.18	%
	Residual cash flows discount rate	8.34	%	10.32	%	9.52	%	7.42	%	10.59	%	9.20	%
	Escrow earn rate	2.06	%	2.49	%	2.31	%	0.94	%	1.22	%	1.10	%
	Loan assumption rate	—	%	1.64	%	1.29	%	—	%	1.75	%	1.44	%

The range and weighted-average of the significant unobservable inputs used to fair value our mortgage servicing assets at March 31, 2022, and March 31, 2021, along with the valuation techniques, are shown in the following table:

		March 31, 2022									March 31, 2021
Valuation Technique	Significant Unobservable Input	Range						Weighted Average			Range						Weighted Average
Discounted cash flow	Prepayment speed	5.84		%	59.51		%	8.82		%	10.55		%	50.81		%	12.82		%
	Discount rate	7.50		%	8.52		%	7.53		%	7.51		%	8.63		%	7.55		%
	Servicing cost	$	62.00		$	8,075		$	67.46		$	62.00		$	4,375		$	72.48