Retirement Plans and Profit Sharing Arrangements (Assets Measured at Fair Value) (Details 6) - Pension Plans [Member] - USD ($) $ in Millions		Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets		$ 838	$ 728	$ 748
Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets		307	266
Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets		24	23
Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets		0	0
U.S. large cap stocks [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets		119	90
U.S. large cap stocks [Member] | Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets		119	90
U.S. small cap stocks [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets		91	70
U.S. small cap stocks [Member] | Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets		91	70
Non-U.S. large cap stocks [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets		32	25
Non-U.S. large cap stocks [Member] | Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets		32	25
Non-U.S. small cap stocks [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets			22
Non-U.S. small cap stocks [Member] | Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets			22
U.S. investment grade bonds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets		67	62
U.S. investment grade bonds [Member] | Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets		43	39
U.S. investment grade bonds [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets		24	23
U.S. high yield bonds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets		6	5
U.S. high yield bonds [Member] | Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets		6	5
Non-U.S. investment grade bonds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets		16	15
Non-U.S. investment grade bonds [Member] | Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets		16	15
Collective investment funds [Member] [Member] | Fair Value Measured at Net Asset Value Per Share [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	[1]	232	188
Real estate investment trusts [Member] | Fair Value Measured at Net Asset Value Per Share [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	[1]	20	19
Hedge funds [Member] | Fair Value Measured at Net Asset Value Per Share [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	[1]	29	27
Pooled pension funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	[1]	196	169
Cash equivalents [Member] | Fair Value Measured at Net Asset Value Per Share [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	[1]	$ 30	$ 36

[1] Amounts are comprised of certain investments that are measured at fair value using the NAV per share (or its equivalent) as a practical expedient and have not been classified in the fair value hierarchy.