Income Taxes And Tax-Related Items Current and Deferred Components of the Provision for Income Taxes (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Document Period End Date									Dec. 31, 2019
Current federal income tax									$ 267	$ 227	$ 371
Current foreign income tax									7	10	5
Current state and local income tax									48	39	36
Total current income tax									322	276	412
Deferred federal income tax									16	29	(26)
Deferred state and local income tax									(4)	3	(2)
Remeasurement of deferred taxes									0	(8)	107
Total deferred income tax									12	24	79
Provision for income taxes	$ 82	$ 80	$ 87	$ 85	$ 90	$ 63	$ 54	$ 93	$ 334	$ 300	$ 491