Retirement and Deferred Compensation Plans (Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Statement [Abstract]
Net periodic benefit expense (recovery)	$ (2)	$ (3)	$ 5
Expected benefit payments in the next fiscal year	110
Defined contribution plans expense	93	88	86
Deferred compensation plans expense	4	35	$ 33
Elective Contribution [Member]
Statement [Abstract]
Pension contributions	$ 8	$ 10