Equity Securities, Net Gains (Losses) Not Held for Trading (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Net Gains (Losses) from Equity Securities [Line Items]
Total net gains (losses) from equity securities not held for trading	$ (1,401)	$ 814
Not designated as hedging instrument [Member]
Net Gains (Losses) from Equity Securities [Line Items]
Net gains (losses) from economic hedge derivatives	7,082	(2,638)
Not designated as hedging instrument [Member] | Net gain (loss) from equity securities [Member]
Net Gains (Losses) from Equity Securities [Line Items]
Net gains (losses) from economic hedge derivatives	1,219	(885)
Economic hedges [Member]
Net Gains (Losses) from Equity Securities [Line Items]
Net gains (losses) from economic hedge derivatives	4,334	(71)
Economic hedges [Member] | Net gain (loss) from equity securities [Member]
Net Gains (Losses) from Equity Securities [Line Items]
Net gains (losses) from economic hedge derivatives	1,219	(885)
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	(1,907)	1,313
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	(803)	377
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	(1,104)	936
Net gain (loss) from nonmarketable equity securities not carried at fair value	(713)	386
Nonmarketable equity securities [Member] | Impairment write-downs [Member]
Net Gains (Losses) from Equity Securities [Line Items]
Net gain (loss) from nonmarketable equity securities not carried at fair value	(935)	(36)
Nonmarketable equity securities [Member] | Net unrealized gains related to 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	222	185
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	0	237
Nonmarketable equity securities [Member] | All other [Member]
Net Gains (Losses) from Equity Securities [Line Items]
Net gain (loss) from nonmarketable equity securities not carried at fair value	$ 0	$ 0