Mortgage Servicing Assets (Tables)

12 Months Ended

Dec. 31, 2011

Mortgage Servicing Assets (Tables) [Abstract]

Changes in the carrying amount of mortgage servicing assets

Year ended December 31 in millions	2011		2010
Balance at beginning of year	$	196	$	221
Servicing retained from loan sales		23		10
Purchases		13		12
Amortization		(59)		(47)
Balance at end of year	$	173	$	196
Fair value at end of year	$	245	$	284