Benefit Plans (Fair Values of Pension and Postretirement Plan Assets) (Details) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Pension [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets, net	$ 6,775	$ 6,603	$ 8,793
Pension [Member] | US Treasury and Government [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets, net	1,114	1,098
Pension [Member] | Municipal Bonds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets, net	81	82
Pension [Member] | Debt Security, Government, Non-US [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets, net	33	32
Pension [Member] | Corporate Debt Security, Above Investment Grade [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets, net	3,160	2,747
Pension [Member] | Corporate Debt Security, Below Investment Grade [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets, net	716	756
Pension [Member] | Common stock: International equities [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets, net	360	327
Pension [Member] | Common stock: U.S. equities [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets, net	323	591
Pension [Member] | Asset-Backed Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets, net	279	161
Pension [Member] | Other, Net [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets, net	201	243
Pension [Member] | U S Large Cap [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets, net	$ 388	$ 312
Defined Benefit Plan, Plan Assets, Fair Value by Hierarchy and NAV [Extensible List]	NAV [Member]	NAV [Member]
Pension [Member] | U S Small Cap [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets, net	$ 90	$ 75
Defined Benefit Plan, Plan Assets, Fair Value by Hierarchy and NAV [Extensible List]	NAV [Member]	NAV [Member]
Pension [Member] | International Developed Markets [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets, net	$ 55	$ 49
Defined Benefit Plan, Plan Assets, Fair Value by Hierarchy and NAV [Extensible List]	NAV [Member]	NAV [Member]
Pension [Member] | Other Investments [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets, net	$ (25)	$ 130
Pension [Member] | Fair Value, Inputs, Level 1, 2 and 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets, net	6,267	6,037
Pension [Member] | Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets, net	730	917
Pension [Member] | Level 1 [Member] | US Treasury and Government [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets, net	0	0
Pension [Member] | Level 1 [Member] | Municipal Bonds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets, net	0	0
Pension [Member] | Level 1 [Member] | Debt Security, Government, Non-US [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets, net	0	0
Pension [Member] | Level 1 [Member] | Corporate Debt Security, Above Investment Grade [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets, net	0	0
Pension [Member] | Level 1 [Member] | Corporate Debt Security, Below Investment Grade [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets, net	0	0
Pension [Member] | Level 1 [Member] | Common stock: International equities [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets, net	360	327
Pension [Member] | Level 1 [Member] | Common stock: U.S. equities [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets, net	323	591
Pension [Member] | Level 1 [Member] | Asset-Backed Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets, net	0	0
Pension [Member] | Level 1 [Member] | Other, Net [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets, net	47	(1)
Pension [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets, net	5,537	5,120
Pension [Member] | Level 2 [Member] | US Treasury and Government [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets, net	1,114	1,098
Pension [Member] | Level 2 [Member] | Municipal Bonds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets, net	81	82
Pension [Member] | Level 2 [Member] | Debt Security, Government, Non-US [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets, net	33	32
Pension [Member] | Level 2 [Member] | Corporate Debt Security, Above Investment Grade [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets, net	3,160	2,747
Pension [Member] | Level 2 [Member] | Corporate Debt Security, Below Investment Grade [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets, net	716	756
Pension [Member] | Level 2 [Member] | Common stock: International equities [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets, net	0	0
Pension [Member] | Level 2 [Member] | Common stock: U.S. equities [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets, net	0	0
Pension [Member] | Level 2 [Member] | Asset-Backed Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets, net	279	161
Pension [Member] | Level 2 [Member] | Other, Net [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets, net	154	244
Pension [Member] | NAV [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets, net	533	436
Postretirement Benefit Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets, net	102	122	$ 185
Postretirement Benefit Plan [Member] | US Treasury and Government [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets, net	4	5
Postretirement Benefit Plan [Member] | Debt Security, Government, Non-US [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets, net	2	2
Postretirement Benefit Plan [Member] | Corporate Debt Security, Above Investment Grade [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets, net	31	37
Postretirement Benefit Plan [Member] | Corporate Debt Security, Below Investment Grade [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets, net	4	7
Postretirement Benefit Plan [Member] | Other, Net [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets, net	4	3
Postretirement Benefit Plan [Member] | U S Large Cap [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets, net	$ 44	$ 47
Defined Benefit Plan, Plan Assets, Fair Value by Hierarchy and NAV [Extensible List]	NAV [Member]	NAV [Member]
Postretirement Benefit Plan [Member] | International Developed Markets [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets, net	$ 11	$ 18
Defined Benefit Plan, Plan Assets, Fair Value by Hierarchy and NAV [Extensible List]	NAV [Member]	NAV [Member]
Postretirement Benefit Plan [Member] | Other Investments [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets, net	$ 2	$ 3
Postretirement Benefit Plan [Member] | Fair Value, Inputs, Level 1, 2 and 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets, net	45	54
Postretirement Benefit Plan [Member] | Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets, net	1	0
Postretirement Benefit Plan [Member] | Level 1 [Member] | US Treasury and Government [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets, net	0	0
Postretirement Benefit Plan [Member] | Level 1 [Member] | Debt Security, Government, Non-US [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets, net	0	0
Postretirement Benefit Plan [Member] | Level 1 [Member] | Corporate Debt Security, Above Investment Grade [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets, net	0	0
Postretirement Benefit Plan [Member] | Level 1 [Member] | Corporate Debt Security, Below Investment Grade [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets, net	0	0
Postretirement Benefit Plan [Member] | Level 1 [Member] | Other, Net [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets, net	1	0
Postretirement Benefit Plan [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets, net	44	54
Postretirement Benefit Plan [Member] | Level 2 [Member] | US Treasury and Government [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets, net	4	5
Postretirement Benefit Plan [Member] | Level 2 [Member] | Debt Security, Government, Non-US [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets, net	2	2
Postretirement Benefit Plan [Member] | Level 2 [Member] | Corporate Debt Security, Above Investment Grade [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets, net	31	37
Postretirement Benefit Plan [Member] | Level 2 [Member] | Corporate Debt Security, Below Investment Grade [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets, net	4	7
Postretirement Benefit Plan [Member] | Level 2 [Member] | Other, Net [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets, net	3	3
Postretirement Benefit Plan [Member] | NAV [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets, net	$ 55	$ 65