Mortgage Servicing Assets (Tables)

3 Months Ended

Mar. 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:

	Three months ended March 31,
in millions	2021		2020
Balance at beginning of period	$	578	$	539
Servicing retained from loan sales	29		24
Purchases	7		11
Amortization	(29)		(29)
Temporary (impairments) recoveries	3		(2)
Balance at end of period	$	588	$	543
Fair value at end of period	$	682	$	655

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

	Three months ended March 31,
in millions	2021		2020
Balance at beginning of period	$	58	$	46
Servicing retained from loan sales	11		5
Purchases	—		—
Amortization	(5)		(2)
Temporary (impairments) recoveries	8		(9)
Balance at end of period	$	72	$	40
Fair value at end of period	$	77	$	41

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, 2021, and March 31, 2020, along with the valuation techniques, are shown in the following table: 

dollars in millions		March 31, 2021					March 31, 2020
Valuation Technique	Significant Unobservable Input	Range			Weighted Average		Range			Weighted Average
Discounted cash flow	Expected defaults	1.01	2.00	%	1.18	%	0.97	2.00	%	1.14	%
	Residual cash flows discount rate	7.42	10.59	%	9.20	%	7.00	11.42	%	9.24	%
	Escrow earn rate	0.94	1.22	%	1.10	%	1.20	1.92	%	1.67	%
	Loan assumption rate	0.00	1.75	%	1.44	%	0.01	3.37	%	1.32	%

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

		March 31, 2021					March 31, 2020
Valuation Technique	Significant Unobservable Input	Range			Weighted Average		Range				Weighted Average
Discounted cash flow	Prepayment speed	10.55	50.81	%	12.82	%	10.50		55.60	%	17.16	%
	Discount rate	7.51	8.63	%	7.55	%	7.50		8.50	%	7.52	%
	Servicing cost	$62.00	4375		72.48		$	62.00	8,375		68.14