Derivatives and Hedge Accounting - Notional amounts and fair values of derivative instruments (Details) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022
Gross Derivative Assets
Notional Amount	$ 184,921	$ 133,721
Fair Value	6,595	6,049
Counterparty netting	(3,864)	(3,895)
Cash Collateral	(2,220)	(1,640)
Total derivative assets	511	514
Gross Derivative Liabilities
Notional Amount	69,672	56,805
Fair Value	5,309	6,043
Counterparty netting	(3,864)	(3,895)
Cash Collateral	(1,050)	(1,917)
Total derivative liabilities on consolidated balance sheet	395	231
Bifurcated embedded derivatives assets, fair value	1,200	2,200
Bifurcated embedded derivative liabilities, fair value	8,000	5,400
Derivatives designated as hedging instruments | Interest rate contracts
Gross Derivative Assets
Notional Amount	1,863	251
Fair Value	230	355
Gross Derivative Liabilities
Notional Amount	752	1,688
Fair Value	17	66
Derivatives designated as hedging instruments | Foreign exchange contracts
Gross Derivative Assets
Notional Amount	3,847	4,543
Fair Value	416	642
Gross Derivative Liabilities
Notional Amount	6,402	4,899
Fair Value	336	317
Derivatives not designated as hedging instruments | Interest rate contracts
Gross Derivative Assets
Notional Amount	42,549	39,833
Fair Value	3,056	3,367
Gross Derivative Liabilities
Notional Amount	42,466	34,128
Fair Value	3,614	4,772
Derivatives not designated as hedging instruments | Foreign exchange contracts
Gross Derivative Assets
Notional Amount	8,803	8,626
Fair Value	820	1,202
Gross Derivative Liabilities
Notional Amount	9,900	10,397
Fair Value	558	821
Derivatives not designated as hedging instruments | Equity contracts
Gross Derivative Assets
Notional Amount	81,110	31,264
Fair Value	2,019	428
Gross Derivative Liabilities
Notional Amount	9,595	4,740
Fair Value	745	26
Derivatives not designated as hedging instruments | Commodity contracts
Gross Derivative Assets
Notional Amount	0	212
Fair Value	0	9
Gross Derivative Liabilities
Notional Amount	0	20
Fair Value	0	0
Derivatives not designated as hedging instruments | Credit contracts
Gross Derivative Assets
Notional Amount	2,109	1,808
Fair Value	41	32
Gross Derivative Liabilities
Notional Amount	509	933
Fair Value	37	41
Derivatives not designated as hedging instruments | Credit contracts | CDS
Gross Derivative Liabilities
Notional Amount	50	79
Fair Value	32	32
Derivatives not designated as hedging instruments | Other contracts
Gross Derivative Assets
Notional Amount	44,640	47,184
Fair Value	13	14
Gross Derivative Liabilities
Notional Amount	48	0
Fair Value	$ 2	$ 0