Income Taxes (Income Tax Components) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income Tax Disclosure [Abstract]
Payable related to accrued interest and penalties	$ 10	$ 8
Current income tax:
Federal	275	468	$ 245
State and local	45	58	44
Foreign	41	52	23
Total current income tax	361	578	312
Deferred income tax:
Federal	20	169	(36)
State and local	2	(5)	3
Foreign	3	(8)	(1)
Total deferred income tax	25	156	(34)
Total income tax provision	386	734	$ 278
Expense related to the enactment of the Tax Act		286
Remeasurement of deferred tax assets and liabilities to Tax Act's statutory 21%		221
Expense for the foreign provisions of the Tax Act		57
Remeasurement of tax contingencies related to the Tax Act		$ 8
Final adjustment related to Tax Act	$ 3