Note 16: Segment Information (Detail) - Segment Total Assets (USD $) In Millions, unless otherwise specified	6 Months Ended	12 Months Ended
	Jun. 30, 2012	Dec. 31, 2011
Segment total assets:
Total of reportable segment total assets	$ 4,618	$ 4,678
Commercial [Member] | Assets [Member]
Segment total assets:
Total of reportable segment total assets	1,825	1,989
Consumer [Member] | Assets [Member]
Segment total assets:
Total of reportable segment total assets	1,052	1,312
Reportable Segment [Member] | Assets [Member]
Segment total assets:
Total of reportable segment total assets	2,877	3,301
Consolidated [Member] | Assets [Member]
Segment total assets:
Total of reportable segment total assets	4,618	4,678
Consolidated [Member] | Cash and marketable securities [Member]
Segment total assets:
Cash and marketable securities	1,262	867
Consolidated [Member] | Deferred income tax assets [Member]
Segment total assets:
Deferred income tax assets	$ 479	$ 510