Equity Securities, Net Gains (Losses) Not Held for Trading (Details) - USD ($) $ in Millions		3 Months Ended		9 Months Ended
		Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Net Gains (Losses) from Equity Securities [Line Items]
Total net gains from equity securities	[1]	$ 956	$ 416	$ 2,392	$ 1,494
Not designated as hedging instrument [Member]
Net Gains (Losses) from Equity Securities [Line Items]
Net gains (losses) recognized related to derivatives not designated as hedging instruments		(226)	(1,749)	(3,854)	(1,204)
Not designated as hedging instrument [Member] | Net gain (loss) from equity securities [Member]
Net Gains (Losses) from Equity Securities [Line Items]
Net gains (losses) recognized related to derivatives not designated as hedging instruments		(1,375)	(719)	(2,918)	(1,317)
Economic hedges [Member]
Net Gains (Losses) from Equity Securities [Line Items]
Net gains (losses) recognized related to derivatives not designated as hedging instruments		(393)	(964)	(96)	(2,010)
Economic hedges [Member] | Net gain (loss) from equity securities [Member]
Net Gains (Losses) from Equity Securities [Line Items]
Net gains (losses) recognized related to derivatives not designated as hedging instruments		(1,375)	(719)	(2,918)	(1,317)
Equity securities [Member] | Net gain (loss) from equity securities [Member]
Net Gains (Losses) from Equity Securities [Line Items]
Net gain (loss) from equity securities carried at fair value		1,593	925	3,902	1,664
Marketable equity securities [Member] | Net gain (loss) from equity securities [Member]
Net Gains (Losses) from Equity Securities [Line Items]
Net gain (loss) from equity securities carried at fair value		116	103	757	139
Nonmarketable equity securities [Member] | Net gain (loss) from equity securities [Member]
Net Gains (Losses) from Equity Securities [Line Items]
Net gain (loss) from equity securities carried at fair value		1,477	822	3,145	1,525
Net gain (loss) from nonmarketable equity securities not carried at fair value		738	210	1,408	1,147
Nonmarketable equity securities [Member] | Impairment write-downs
Net Gains (Losses) from Equity Securities [Line Items]
Net gain (loss) from nonmarketable equity securities not carried at fair value		(43)	(45)	(110)	(302)
Nonmarketable equity securities [Member] | Measurement alternative observable transactions [Member]
Net Gains (Losses) from Equity Securities [Line Items]
Net gain (loss) from nonmarketable equity securities not carried at fair value		158	51	489	314
Nonmarketable equity securities [Member] | Realized gains on sale [Member]
Net Gains (Losses) from Equity Securities [Line Items]
Net gain (loss) from nonmarketable equity securities not carried at fair value		623	204	1,029	1,101
Nonmarketable equity securities [Member] | Other [Member]
Net Gains (Losses) from Equity Securities [Line Items]
Net gain (loss) from nonmarketable equity securities not carried at fair value		$ 0	$ 0	$ 0	$ 34

[1] (2) Includes OTTI losses of $43 million and $45 million for third quarter 2019 and 2018, respectively, and $110 million and $302 million for the first nine months of 2019 and 2018, respectively.