Accumulated Other Comprehensive Income (Loss), Net of Tax (Changes of AOCI) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021	Dec. 31, 2021
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Accumulated Other Comprehensive Income (Loss), Beginning Balance	$ (455)	$ (522)	$ (350)	$ (504)	$ (504)
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	(48)	(4)	(166)	(28)
Amounts Reclassified from Accumulated Other Comprehensive Income (Loss)	10	2	23	8
Other Comprehensive Income (Loss), net of tax	(38)	(2)	(143)	(20)
Accumulated Other Comprehensive Income (Loss), Ending Balance	(493)	(524)	(493)	(524)	(350)
Cash Flow Hedges [Member]
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Accumulated Other Comprehensive Income (Loss), Beginning Balance	(5)	(8)	(6)	(9)	(9)
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	0	0	0	0	0
Amounts Reclassified from Accumulated Other Comprehensive Income (Loss)	1	1	2	2	3
Other Comprehensive Income (Loss), net of tax	1	1	2	2
Accumulated Other Comprehensive Income (Loss), Ending Balance	(4)	(7)	(4)	(7)	(6)
Pension and OPEB Plans [Member]
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Accumulated Other Comprehensive Income (Loss), Beginning Balance	(354)	(538)	(355)	(545)	(545)
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	0	0	0	0
Amounts Reclassified from Accumulated Other Comprehensive Income (Loss)	0	4	1	11
Other Comprehensive Income (Loss), net of tax	0	4	1	11
Accumulated Other Comprehensive Income (Loss), Ending Balance	(354)	(534)	(354)	(534)	(355)
Available-for-Sale Securities [Member]
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Accumulated Other Comprehensive Income (Loss), Beginning Balance	(96)	24	11	50	50
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	(48)	(4)	(166)	(28)
Amounts Reclassified from Accumulated Other Comprehensive Income (Loss)	9	(3)	20	(5)
Other Comprehensive Income (Loss), net of tax	(39)	(7)	(146)	(33)
Accumulated Other Comprehensive Income (Loss), Ending Balance	$ (135)	$ 17	$ (135)	$ 17	$ 11