Retirement and Deferred Compensation Plans (Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Statement [Abstract]
Net periodic benefit expense (recovery)	$ (6)	$ (4)	$ (1)
Expected benefit payments in the next fiscal year	132
Increase (decrease) in pension plan obligations		55
Defined contribution plans expense	82	78	72
Deferred compensation plans expense	10	23	$ 38
Required Contribution [Member]
Statement [Abstract]
Pension contributions	11	$ 6
Elective Contribution [Member]
Statement [Abstract]
Pension contributions	$ 25