Employee Benefits (Defined Pension Benefits In Excess Of Qualified Plan Limits, Information For The SERPs) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Non-Qualified SERPs [Member]
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Defined benefit plan, benefit obligation, beginning balance	$ 173	$ 165
Service cost	1	1	1
Interest cost	7	8	10
Actuarial gain (losses)	13	23
Benefits paid	(2)	(2)
Settlements	(20)	(22)
Defined benefit plan, benefit obligation, ending balance	172	173	165
Funded status (plan assets less benefit obligations)	(172)	(173)
Net accrued benefit expense	(172)	(173)
Current liabilities	(15)	(27)
Non-current liabilities	(157)	(146)
Net accrued amount recognized in consolidated statement of condition	(172)	(173)
Net loss	(59)	(58)
Accumulated other comprehensive loss	(59)	(58)
Cumulative employer contributions in excess of net periodic benefit cost	(113)	(115)
Net obligation recognized in consolidated statement of condition	(172)	(173)
Accumulated benefit obligation	$ 172	$ 173
SERPs [Member]
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Used to determine benefit obligations, Rate of increase for future compensation	0.00%	0.00%
Executive SERPs [Member]
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Used to determine benefit obligations, Rate of increase for future compensation	10.00%	10.00%