Equity Securities, Net Gains (Losses) Not Held for Trading (Details) - USD ($) $ in Millions		3 Months Ended		6 Months Ended
		Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Net Gains (Losses) from Equity Securities [Line Items]
Total net gains from equity securities	[1]	$ 622	$ 295	$ 1,436	$ 1,078
Not designated as hedging instrument [Member]
Net Gains (Losses) from Equity Securities [Line Items]
Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net		(990)	595	(3,628)	545
Not designated as hedging instrument [Member] | Net gain (loss) from equity securities [Member]
Net Gains (Losses) from Equity Securities [Line Items]
Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net		(658)	(540)	(1,543)	(598)
Economic hedges [Member] | Not designated as hedging instrument [Member]
Net Gains (Losses) from Equity Securities [Line Items]
Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net		368	(247)	297	(1,046)
Economic hedges [Member] | Not designated as hedging instrument [Member] | Net gain (loss) from equity securities [Member]
Net Gains (Losses) from Equity Securities [Line Items]
Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net		(658)	(540)	(1,543)	(598)
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		996	622	2,309	739
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		264	28	641	36
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		732	594	1,668	703
Net gain (loss) from nonmarketable equity securities not carried at fair value		284	213	670	937
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		(31)	(237)	(67)	(257)
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		146	35	331	263
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		169	399	406	897
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	$ 16	$ 0	$ 34

[1] (2) Includes OTTI losses of $31 million and $237 million for second quarter 2019 and 2018, respectively, and $67 million and $257 million for the first half of 2019 and 2018, respectively.