Retirement Plans and Profit Sharing Arrangements (Benefit Obligation and Fair Value) (Details 2) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Pension Plans [Member]
Change in benefit obligation
Benefit obligation at beginning of year	$ 1,111	$ 967
Service cost	45	44	$ 48
Interest cost	29	36	30
Defined Benefit Plan, Benefit Obligation, Increase (Decrease) for Other Change	0	(15)
Benefits paid	(10)	(9)
Actuarial (gain) loss	117	131
Defined Benefit Plan, Benefit Obligation, (Increase) Decrease for Curtailment	0	(7)
Settlements	(30)	(42)
Foreign currency rate changes	9	6
Benefit obligation at end of year	1,271	1,111	967
Change in fair value of plan assets
Fair value of plan assets at the beginning of the year	838	728
Actual return on plan assets	67	130
Employer contributions	31	24
Benefits paid	(10)	(9)
Settlements	(30)	(42)
Foreign currency rate changes	9	7
Fair value of plan assets at the end of the year	905	838	728
Other Postretirement Benefits Plan [Member]
Change in benefit obligation
Benefit obligation at beginning of year	14	14
Interest cost	0
Benefits paid	(1)	(1)
Actuarial (gain) loss	1	1
Benefit obligation at end of year	$ 14	$ 14	$ 14