Condensed Consolidated Statements of Changes in Equity - Piedmont - USD ($) $ in Millions	Total	Common Stock	Retained Earnings	Total Equity	Noncontrolling Interests	Piedmont	Piedmont Common Stock	Piedmont Retained Earnings	Piedmont Total Equity	Piedmont Noncontrolling Interests
Beginning Balance (Attributable to Parent) at Dec. 31, 2022		$ 1	$ 2,637	$ 49,322			$ 1,635	$ 2,037	$ 3,672
Beginning Balance (Attributable to Noncontrolling Interest) at Dec. 31, 2022					$ 2,531					$ 1
Beginning Balance (Parent) at Dec. 31, 2022	$ 51,853					$ 3,673
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	761					232		232	232
Ending Balance (Attributable to Parent) at Mar. 31, 2023		1	2,626	49,260			1,635	2,269	3,904
Ending Balance (Attributable to Noncontrolling Interest) at Mar. 31, 2023					2,691					1
Ending Balance (Parent) at Mar. 31, 2023	51,951					3,905
Beginning Balance (Attributable to Parent) at Dec. 31, 2023	49,112	1	2,235	49,112		4,051	1,635	2,416	4,051
Beginning Balance (Attributable to Noncontrolling Interest) at Dec. 31, 2023	1,075				1,075	1				1
Beginning Balance (Parent) at Dec. 31, 2023	50,187					4,052
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	1,151					246		246	246
Ending Balance (Attributable to Parent) at Mar. 31, 2024	49,551	$ 1	$ 2,542	$ 49,551		4,297	$ 1,635	$ 2,662	$ 4,297
Ending Balance (Attributable to Noncontrolling Interest) at Mar. 31, 2024	1,087				$ 1,087	1				$ 1
Ending Balance (Parent) at Mar. 31, 2024	$ 50,638					$ 4,298