Retirement Plans and Profit Sharing Arrangements (Assets Measured at Fair Value) (Details 6) - Pension Plans [Member] - USD ($) $ in Millions		Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets		$ 728	$ 748	$ 628
Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets		266	307
Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets		23	11
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		90	98
U.S. large cap stocks [Member] | Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets		90	98
U.S. small cap stocks [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets		70	80
U.S. small cap stocks [Member] | Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets		70	80
Non-U.S. large cap stocks [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets		25	28
Non-U.S. large cap stocks [Member] | Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets		25	28
Non-U.S. small cap stocks [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets		22	28
Non-U.S. small cap stocks [Member] | Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets		22	28
Emerging markets [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets			25
Emerging markets [Member] | Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets			25
U.S. investment grade bonds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets		62	38
U.S. investment grade bonds [Member] | Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets		39	27
U.S. investment grade bonds [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets		23	11
U.S. high yield bonds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets		5	5
U.S. high yield bonds [Member] | Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets		5	5
Non-U.S. investment grade bonds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets		15	16
Non-U.S. investment grade bonds [Member] | Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets		15	16
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]	188	181
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]	19	18
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]	27	27
Pooled pension funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets		169	186
Cash equivalents [Member] | Fair Value Measured at Net Asset Value Per Share [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets		$ 36	$ 18

[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.