Employee Benefit Plans (Narrative) (Details) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Employee benefits expense	$ 88,000,000	$ 81,000,000	$ 53,000,000
Estimated average life of pension plan in years	15
Fair value of plan assets in defined benefit pension plan	2,028,000,000	1,953,000,000
Estimated employer contributions for defined benefit plans in year 2014	0
Employer core matching cash contribution as percent of employee contribution	100.00%
Percent of qualified earnings contributed by employee matched by the Corporation	4.00%
Defined contribution plan expense	20,000,000	20,000,000	20,000,000
Profit sharing plan annual contribution to the individual account of each eligible employee, minimum percent of annual compensation	3.00%
Profit sharing plan annual contribution to the individual account of each eligible employee, maximum percent of annual compensation	8.00%
Profit sharing plan expense included in employee benefits expense	7,000,000	7,000,000	4,000,000
Equity securities
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Target allocation, minimum percent	41.00%
Target allocation, maximum percent	51.00%
Debt securities
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Target allocation, minimum percent	49.00%
Target allocation, maximum percent	59.00%
Defined Benefit Pension Plans
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Employee benefits expense	86,000,000	75,000,000	47,000,000
Defined Benefit Pension Plans | Non-Qualified Plan
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Employee benefits expense	18,000,000	19,000,000	19,000,000
Fair value of plan assets in defined benefit pension plan	0	0
Postretirement Benefit Plan
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Employee benefits expense	2,000,000	6,000,000	6,000,000
Fair value of plan assets in defined benefit pension plan	$ 67,000,000	$ 72,000,000	$ 69,000,000