Retirement and Deferred Compensation Plans (Benefit Plans' Assets and Obligations) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	$ 1,589	$ 1,420
Pension Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	1,520	1,356
Projected benefit obligation	1,646	1,477
Funded status	(126)	(121)
Amounts Recognized on the Consolidated Balance Sheets
Other assets	12	52
Other liabilities	(138)	(173)
Net amount recognized	$ (126)	$ (121)
Weighted-Average Assumptions, Benefit obligations:
Weighted-average discount rate	3.14%	4.14%
Weighted-Average Assumptions, Net periodic benefit cost:
Weighted-average discount rate	4.10%	3.75%
Expected return on plan assets	6.48%	6.46%
Other Postretirement Benefit Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	$ 69	$ 64
Projected benefit obligation	78	74
Funded status	(9)	(10)
Amounts Recognized on the Consolidated Balance Sheets
Other liabilities	(9)	(10)
Net amount recognized	$ (9)	$ (10)
Weighted-Average Assumptions, Benefit obligations:
Weighted-average discount rate	3.50%	4.50%
Weighted-Average Assumptions, Net periodic benefit cost:
Weighted-average discount rate	4.50%	4.00%
Expected return on plan assets	6.50%	6.50%