Retirement Plans and Profit Sharing Arrangements (Benefit Obligations that Exceeded the Fair Value) (Details 4) - Pension Plans [Member] - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Defined Benefit Plan Disclosure [Line Items]
Accumulated benefit obligation	$ 916	$ 822
Plans with accumulated benefit obligations in excess of plan assets:
Accumulated benefit obligation	759	684
Fair value of plan assets	562	469
Plans with projected benefit obligations in excess of plan assets:
Projected benefit obligation	816	899
Fair value of plan assets	$ 562	$ 628