Premises and Equipment Leases (Details) $ in Millions	Dec. 31, 2015 USD ($)
Operating Leased Assets [Line Items]
Operating Leases, Future Minimum Payments Due, Next Twelve Months	$ 207
Operating Leases, Future Minimum Payments, Due in Two Years	192
Operating Leases, Future Minimum Payments, Due in Three Years	122
Operating Leases, Future Minimum Payments, Due in Four Years	103
Operating Leases, Future Minimum Payments, Due in Five Years	81
Operating Leases, Future Minimum Payments, Due Thereafter	307
Operating Leases, Future Minimum Payments Due	$ 1,012