Mortgage Servicing Assets (Tables)

3 Months Ended

Mar. 31, 2019

Servicing Asset [Abstract]

Changes in Carrying Amount of Mortgage Servicing Assets

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

	Three months ended March 31,
in millions	2019			2018
Balance at beginning of period	$	37		$	31
Servicing retained from loan sales	2			2
Purchases	—			—
Amortization	(1		)	(1		)
Balance at end of period	$	38		$	32
Fair value at end of period	$	50		$	42

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

	Three months ended March 31,
in millions	2019			2018
Balance at beginning of period	$	502		$	412
Servicing retained from loan sales	18			27
Purchases	6			21
Amortization	(29		)	(25		)
Balance at end of period	$	497		$	435
Fair value at end of period	$	727		$	537

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, 2019, and March 31, 2018, along with the valuation techniques, are shown in the following table: 

dollars in millions		March 31, 2019	March 31, 2018
Valuation Technique	Significant Unobservable Input	Range (Weighted Average)
Discounted cash flow	Expected defaults	1.00 - 2.00% (1.14%)	1.00 - 3.00% (1.18%)
	Residual cash flows discount rate	7.00 - 15.00% (9.19%)	7.00 - 15.00% (8.99%)
	Escrow earn rate	2.22 - 3.70% (2.98%)	2.17 - 3.45% (2.84%)
	Loan assumption rate	0.00 - 3.18% (1.39%)	0.00 - 2.84% (1.18%)

The range and weighted-average of the significant unobservable inputs used to fair value our mortgage servicing assets at March 31, 2019, and March 31, 2018, along with the valuation techniques, are shown in the following table:

dollars in millions		March 31, 2019	March 31, 2018
Valuation Technique	Significant Unobservable Input	Range (Weighted Average)
Discounted cash flow	Prepayment speed	9.32 - 58.76% (9.93%)	8.37 - 48.63% (9.12%)
	Discount rate	7.50 - 10.00% (7.54%)	8.50 - 11.00% (8.54%)
	Servicing cost	$62 - $4,375 ($68.23)	$76 - $4,385 ($83.05)