Schedule I - Condensed Financial Information of Parent (Balance Sheet) (Details) - USD ($)	Dec. 31, 2020	Jan. 01, 2020	Dec. 31, 2019	Jun. 30, 2019	Jan. 01, 2019	Dec. 31, 2018	Dec. 31, 2016
Current Assets:
Cash and cash equivalents	$ 1,089,000,000		$ 1,029,000,000
Restricted cash	297,000,000		336,000,000
Assets, Current	5,414,000,000		5,231,000,000
Investment in and advances to subsidiaries and affiliates	835,000,000		966,000,000			$ 1,114,000,000
Office Equipment:
Cost	26,707,000,000		25,383,000,000
Accumulated depreciation	(8,472,000,000)		(8,505,000,000)
Property, plant and equipment, net	22,826,000,000		22,574,000,000
Other Assets:
Deferred income taxes	288,000,000		156,000,000
Other assets	1,660,000,000	$ 1,605,000,000	1,635,000,000		$ 1,767,000,000
Total other assets	6,363,000,000		5,843,000,000
Assets	34,603,000,000		33,648,000,000			32,521,000,000
Current Liabilities:
Accounts payable	1,156,000,000		1,311,000,000
Accrued and other liabilities	1,223,000,000		987,000,000		989,000,000
Total current liabilities	5,362,000,000		5,096,000,000
Long-term Liabilities:
Other long-term liabilities	3,241,000,000		2,917,000,000		$ 2,949,000,000
Liabilities, Noncurrent	23,649,000,000		22,435,000,000
Stockholders' equity:
Common stock	8,000,000		8,000,000	$ 14.16
Additional paid-in capital	7,561,000,000		7,776,000,000
Accumulated deficit	(680,000,000)	$ (731,000,000)	(692,000,000)
Accumulated other comprehensive loss	(2,397,000,000)		(2,229,000,000)			(2,071,000,000)
Treasury stock	(1,858,000,000)		(1,867,000,000)
Total AES Corporation stockholders’ equity	2,634,000,000		2,996,000,000
TOTAL LIABILITIES AND EQUITY	34,603,000,000		33,648,000,000
Parent Company [Member]
Current Assets:
Cash and cash equivalents	70,000,000		11,000,000			$ 19,000,000	$ 10,000,000
Accounts and notes receivable from subsidiaries	188,000,000		238,000,000
Prepaid expenses and other current assets	55,000,000		35,000,000
Assets, Current	313,000,000		284,000,000
Investment in and advances to subsidiaries and affiliates	6,426,000,000		6,782,000,000
Office Equipment:
Cost	29,000,000		27,000,000
Accumulated depreciation	(22,000,000)		(20,000,000)
Property, plant and equipment, net	7,000,000		7,000,000
Other Intangible Assets, Net	0		1,000,000
Other Assets:
Debt Issuance Costs, Noncurrent, Net	4,000,000		5,000,000
Deferred income taxes	25,000,000		14,000,000
Other assets	20,000,000		16,000,000
Total other assets	49,000,000		36,000,000
Assets	6,795,000,000		7,109,000,000
Current Liabilities:
Accounts payable	15,000,000		20,000,000
Accounts and notes payable to subsidiaries	184,000,000		339,000,000
Accrued and other liabilities	344,000,000		221,000,000
Senior notes payable—current portion	0		5,000,000
Total current liabilities	543,000,000		585,000,000
Long-term Liabilities:
Senior notes payable	3,430,000,000		3,391,000,000
Accounts and notes payable to subsidiaries	28,000,000		28,000,000
Other long-term liabilities	160,000,000		109,000,000
Liabilities, Noncurrent	3,618,000,000		3,528,000,000
Stockholders' equity:
Common stock	8,000,000		8,000,000
Additional paid-in capital	7,561,000,000		7,776,000,000
Accumulated deficit	(680,000,000)		(692,000,000)
Accumulated other comprehensive loss	(2,397,000,000)		(2,229,000,000)
Treasury stock	(1,858,000,000)		(1,867,000,000)
Total AES Corporation stockholders’ equity	2,634,000,000		2,996,000,000
TOTAL LIABILITIES AND EQUITY	6,795,000,000		7,109,000,000
Accumulated Amortization, Debt Issuance Costs, Noncurrent	$ 6,000,000		$ 5,000,000