Mortgage Servicing Assets (Tables)

12 Months Ended

Dec. 31, 2021

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:

Year ended December 31, Dollars in millions	2021		2020
Balance at beginning of period	$	578	$	539
Servicing retained from loan sales	128		138
Purchases	29		33
Amortization	(120)		(117)
Temporary recoveries (impairments)	19		(15)
Balance at end of period	$	634	$	578
Fair value at end of period	$	789	$	668

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

Dollars in millions	2021		2020
Balance at beginning of period	$	58	$	46
Servicing retained from loan sales	43		36
Purchases	—		—
Amortization	(18)		(14)
Temporary recoveries (impairments)	10		(10)
Balance at end of period	$	93	$	58
Fair value at end of period	$	97	$	60

Schedule of Range and Weighted-Average of Significant Unobservable Inputs

The range and weighted-average of the significant unobservable inputs used to fair value our commercial mortgage servicing assets at December 31, 2021, and December 31, 2020, along with the valuation techniques, are shown in the following table:

dollars in millions		December 31, 2021						December 31, 2020
Valuation Technique	Significant Unobservable Input	Range				Weighted-Average		Range				Weighted-Average
Discounted cash flow	Expected defaults	1.00	%	2.00	%	1.13	%	1.01	%	2.00	%	1.18	%
	Residual cash flows discount rate	7.92	%	10.46	%	9.44	%	7.48	%	10.62	%	9.22	%
	Escrow earn rate	1.34	%	1.74	%	1.34	%	0.92	%	1.14	%	1.04	%
	Loan assumption rate	—	%	1.69	%	1.37	%	—	%	1.77	%	1.43	%

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

		December 31, 2021									December 31, 2020
Valuation Technique	Significant Unobservable Input	Range						Weighted-Average			Range						Weighted-Average
Discounted cash flow	Prepayment speed	9.65		%	49.17		%	10.97		%	12.39		%	54.27		%	17.09		%
	Discount rate	7.50		%	11.50		%	7.53		%	7.51		%	8.63		%	7.55		%
	Servicing cost	$	62.00		$	8,075		$	66.94		$	62.00		$	5,125		$	75.37