Retirement and Deferred Compensation Plans (Deferred Compensation Plans Liabilities and Investment) (Details) - USD ($) $ in Millions		Dec. 31, 2017	Dec. 31, 2016
Defined Contribution Pension and Other Postretirement Plans Disclosure [Abstract]
Total liabilities		$ 588	$ 514
Investments dedicated to fund liabilities	[1]	$ 182	$ 159

[1] Reported in other liabilities on our Consolidated Balance Sheets.