Retirement and Deferred Compensation Plans (Benefit Plans' Assets and Obligations) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Pension Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	$ 1,434	$ 1,522
Projected benefit obligation	1,607	1,708
Funded status of plan	(173)	(186)
Amounts Recognized on the Consolidated Balance Sheets
Other assets	28	34
Other liabilities	(201)	(220)
Net amount recognized	$ (173)	$ (186)
Weighted-Average Assumptions, Benefit obligations:
Weighted-average discount rate	4.29%	3.88%
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract]
Weighted-average discount rate	3.88%	4.64%
Expected return on plan assets	6.87%	6.90%
Other Postretirement Benefit Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	$ 52	$ 48
Projected benefit obligation	97	103
Funded status of plan	(45)	(55)
Amounts Recognized on the Consolidated Balance Sheets
Other assets	2	1
Other liabilities	(47)	(56)
Net amount recognized	$ (45)	$ (55)
Weighted-Average Assumptions, Benefit obligations:
Weighted-average discount rate	4.50%	4.00%
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract]
Weighted-average discount rate	4.00%	4.50%
Expected return on plan assets	6.50%	6.50%