Components of Other Comprehensive Income (Loss), Net - EEGH (Details) - USD ($) $ in Millions	1 Months Ended	3 Months Ended		9 Months Ended
	Jul. 31, 2020	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Balance	$ 33,785	$ 49,365	$ 33,785	$ 46,977	$ 32,578
Other comprehensive income (loss)		(163)	242	33	(177)
Balance		49,616	36,869	49,616	36,869
EEGH
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Balance	8,456	7,398	8,456	6,995	10,229
Other comprehensive income (loss)		(2)	107	15	23
Balance		7,390	6,550	7,390	6,550
Amount of loss reclassified from AOCI to income	141
Amount of loss reclassified from AOCI to income, after-tax	105
Unrecognized Amounts on Retirement Benefits
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Balance				(492)	(417)
Other comprehensive income (loss)				44	38
Balance		(448)	(379)	(448)	(379)
Unrecognized Amounts on Retirement Benefits | EEGH
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Balance				(12)	(106)
Other comprehensive income (loss)				4	(1)
Balance		(8)	(107)	(8)	(107)
Unrealized Losses on Cash Flow Hedges
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Balance				(8)	7
Other comprehensive income (loss)				48	(20)
Balance		40	(13)	40	(13)
Unrealized Losses on Cash Flow Hedges | EEGH
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Balance				(51)	(81)
Other comprehensive income (loss)				11	24
Balance		(40)	(57)	(40)	(57)
Noncontrolling Interest
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Balance				(10)	0
Other comprehensive income (loss)				4	0
Balance		(6)	0	(6)	0
Noncontrolling Interest | EEGH
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Balance				(10)	0
Other comprehensive income (loss)				4	0
Balance		(6)	0	(6)	0
Accumulated Other Comprehensive (Loss) Income, Net
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Balance	(2,125)	(1,360)	(2,125)	(1,552)	(1,706)
Other comprehensive income (loss)		(163)	242	29	(177)
Balance		(1,523)	(1,883)	(1,523)	(1,883)
Accumulated Other Comprehensive (Loss) Income, Net | EEGH
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Balance	$ (271)	(40)	(271)	(53)	(187)
Other comprehensive income (loss)		(2)	107	11	23
Balance		$ (42)	$ (164)	$ (42)	$ (164)