Fair value measurement - Certain Items on Recurring Basis (Details) - Measured at fair value on a recurring basis - USD ($) $ in Millions	Sep. 30, 2021	Dec. 31, 2020
Non-agency RMBS | Origination in 2004 and Earlier, 2005, 2006 and 2007 through 2021
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Total carrying value	$ 387	$ 487
Non-agency RMBS
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Total carrying value	$ 2,598	$ 2,326
Non-agency RMBS | AAA/ AA-
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	78.00%	69.00%
Non-agency RMBS | A/ A-
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	3.00%	3.00%
Non-agency RMBS | BBB/ BBB-
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	0.00%	1.00%
Non-agency RMBS | BB and lower
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	9.00%	16.00%
Non-agency RMBS | A1+/A2/SP-1
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	0.00%	0.00%
Non-agency RMBS | Not Rated
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	10.00%	11.00%
Non-agency RMBS | 2008-2021
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Total carrying value	$ 1,996	$ 1,548
Non-agency RMBS | 2008-2021 | AAA/ AA-
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	100.00%	100.00%
Non-agency RMBS | 2008-2021 | A/ A-
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	0.00%	0.00%
Non-agency RMBS | 2008-2021 | BBB/ BBB-
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	0.00%	0.00%
Non-agency RMBS | 2008-2021 | BB and lower
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	0.00%	0.00%
Non-agency RMBS | 2008-2021 | A1+/A2/SP-1
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	0.00%	0.00%
Non-agency RMBS | 2008-2021 | Not Rated
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	0.00%	0.00%
Non-agency RMBS | 2007
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Total carrying value	$ 124	$ 179
Non-agency RMBS | 2007 | AAA/ AA-
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	0.00%	12.00%
Non-agency RMBS | 2007 | A/ A-
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	4.00%	3.00%
Non-agency RMBS | 2007 | BBB/ BBB-
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	0.00%	0.00%
Non-agency RMBS | 2007 | BB and lower
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	40.00%	42.00%
Non-agency RMBS | 2007 | A1+/A2/SP-1
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	0.00%	0.00%
Non-agency RMBS | 2007 | Not Rated
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	56.00%	43.00%
Non-agency RMBS | 2006
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Total carrying value	$ 194	$ 237
Non-agency RMBS | 2006 | AAA/ AA-
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	0.00%	0.00%
Non-agency RMBS | 2006 | A/ A-
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	24.00%	23.00%
Non-agency RMBS | 2006 | BBB/ BBB-
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	0.00%	0.00%
Non-agency RMBS | 2006 | BB and lower
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	33.00%	40.00%
Non-agency RMBS | 2006 | A1+/A2/SP-1
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	0.00%	0.00%
Non-agency RMBS | 2006 | Not Rated
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	43.00%	37.00%
Non-agency RMBS | 2005
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Total carrying value	$ 179	$ 227
Non-agency RMBS | 2005 | AAA/ AA-
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	3.00%	3.00%
Non-agency RMBS | 2005 | A/ A-
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	5.00%	0.00%
Non-agency RMBS | 2005 | BBB/ BBB-
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	1.00%	7.00%
Non-agency RMBS | 2005 | BB and lower
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	40.00%	52.00%
Non-agency RMBS | 2005 | A1+/A2/SP-1
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	0.00%	0.00%
Non-agency RMBS | 2005 | Not Rated
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	51.00%	38.00%
Non-agency RMBS | 2004 and earlier
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Total carrying value	$ 105	$ 135
Non-agency RMBS | 2004 and earlier | AAA/ AA-
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	16.00%	19.00%
Non-agency RMBS | 2004 and earlier | A/ A-
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	10.00%	10.00%
Non-agency RMBS | 2004 and earlier | BBB/ BBB-
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	5.00%	11.00%
Non-agency RMBS | 2004 and earlier | BB and lower
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	57.00%	54.00%
Non-agency RMBS | 2004 and earlier | A1+/A2/SP-1
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	0.00%	0.00%
Non-agency RMBS | 2004 and earlier | Not Rated
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	12.00%	6.00%
Non-agency commercial MBS | 2009-2021 | Domestic
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Total carrying value	$ 3,182	$ 3,017
Non-agency commercial MBS | 2009-2021 | AAA/ AA- | Domestic
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	100.00%	99.00%
Non-agency commercial MBS | 2009-2021 | A/ A- | Domestic
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	0.00%	1.00%
Non-agency commercial MBS | 2009-2021 | BBB/ BBB- | Domestic
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	0.00%	0.00%
Non-agency commercial MBS | 2009-2021 | BB and lower | Domestic
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	0.00%	0.00%
Non-agency commercial MBS | 2009-2021 | A1+/A2/SP-1 | Domestic
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	0.00%	0.00%
Non-agency commercial MBS | 2009-2021 | Not Rated | Domestic
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	0.00%	0.00%
Foreign covered bonds
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Total carrying value	$ 6,946	$ 6,725
Foreign covered bonds | AAA/ AA-
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	100.00%	100.00%
Foreign covered bonds | A/ A-
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	0.00%	0.00%
Foreign covered bonds | BBB/ BBB-
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	0.00%	0.00%
Foreign covered bonds | BB and lower
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	0.00%	0.00%
Foreign covered bonds | A1+/A2/SP-1
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	0.00%	0.00%
Foreign covered bonds | Not Rated
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	0.00%	0.00%
Foreign covered bonds | Canada
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Total carrying value	$ 2,537	$ 2,552
Foreign covered bonds | Canada | AAA/ AA-
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	100.00%	100.00%
Foreign covered bonds | Canada | A/ A-
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	0.00%	0.00%
Foreign covered bonds | Canada | BBB/ BBB-
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	0.00%	0.00%
Foreign covered bonds | Canada | BB and lower
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	0.00%	0.00%
Foreign covered bonds | Canada | A1+/A2/SP-1
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	0.00%	0.00%
Foreign covered bonds | Canada | Not Rated
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	0.00%	0.00%
Foreign covered bonds | UK
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Total carrying value	$ 1,220	$ 1,259
Foreign covered bonds | UK | AAA/ AA-
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	100.00%	100.00%
Foreign covered bonds | UK | A/ A-
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	0.00%	0.00%
Foreign covered bonds | UK | BBB/ BBB-
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	0.00%	0.00%
Foreign covered bonds | UK | BB and lower
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	0.00%	0.00%
Foreign covered bonds | UK | A1+/A2/SP-1
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	0.00%	0.00%
Foreign covered bonds | UK | Not Rated
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	0.00%	0.00%
Foreign covered bonds | Australia
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Total carrying value	$ 865	$ 951
Foreign covered bonds | Australia | AAA/ AA-
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	100.00%	100.00%
Foreign covered bonds | Australia | A/ A-
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	0.00%	0.00%
Foreign covered bonds | Australia | BBB/ BBB-
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	0.00%	0.00%
Foreign covered bonds | Australia | BB and lower
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	0.00%	0.00%
Foreign covered bonds | Australia | A1+/A2/SP-1
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	0.00%	0.00%
Foreign covered bonds | Australia | Not Rated
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	0.00%	0.00%
Foreign covered bonds | Norway
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Total carrying value	$ 621	$ 703
Foreign covered bonds | Norway | AAA/ AA-
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	100.00%	100.00%
Foreign covered bonds | Norway | A/ A-
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	0.00%	0.00%
Foreign covered bonds | Norway | BBB/ BBB-
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	0.00%	0.00%
Foreign covered bonds | Norway | BB and lower
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	0.00%	0.00%
Foreign covered bonds | Norway | A1+/A2/SP-1
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	0.00%	0.00%
Foreign covered bonds | Norway | Not Rated
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	0.00%	0.00%
Foreign covered bonds | Germany
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Total carrying value	$ 666	$ 494
Foreign covered bonds | Germany | AAA/ AA-
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	100.00%	100.00%
Foreign covered bonds | Germany | A/ A-
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	0.00%	0.00%
Foreign covered bonds | Germany | BBB/ BBB-
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	0.00%	0.00%
Foreign covered bonds | Germany | BB and lower
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	0.00%	0.00%
Foreign covered bonds | Germany | A1+/A2/SP-1
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	0.00%	0.00%
Foreign covered bonds | Germany | Not Rated
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	0.00%	0.00%
Foreign covered bonds | Other
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Total carrying value	$ 1,037	$ 766
Foreign covered bonds | Other | AAA/ AA-
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	100.00%	100.00%
Foreign covered bonds | Other | A/ A-
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	0.00%	0.00%
Foreign covered bonds | Other | BBB/ BBB-
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	0.00%	0.00%
Foreign covered bonds | Other | BB and lower
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	0.00%	0.00%
Foreign covered bonds | Other | A1+/A2/SP-1
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	0.00%	0.00%
Foreign covered bonds | Other | Not Rated
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	0.00%	0.00%
Sovereign Debt
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Total carrying value	$ 13,069	$ 12,391
Sovereign Debt | AAA/ AA-
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	75.00%	62.00%
Sovereign Debt | A/ A-
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	5.00%	6.00%
Sovereign Debt | BBB/ BBB-
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	19.00%	31.00%
Sovereign Debt | BB and lower
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	1.00%	1.00%
Sovereign Debt | A1+/A2/SP-1
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	0.00%	0.00%
Sovereign Debt | Not Rated
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	0.00%	0.00%
Sovereign Debt | Canada
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Total carrying value	$ 651	$ 572
Sovereign Debt | Canada | AAA/ AA-
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	100.00%	100.00%
Sovereign Debt | Canada | A/ A-
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	0.00%	0.00%
Sovereign Debt | Canada | BBB/ BBB-
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	0.00%	0.00%
Sovereign Debt | Canada | BB and lower
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	0.00%	0.00%
Sovereign Debt | Canada | A1+/A2/SP-1
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	0.00%	0.00%
Sovereign Debt | Canada | Not Rated
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	0.00%	0.00%
Sovereign Debt | UK
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Total carrying value	$ 1,203	$ 1,089
Sovereign Debt | UK | AAA/ AA-
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	99.00%	100.00%
Sovereign Debt | UK | A/ A-
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	0.00%	0.00%
Sovereign Debt | UK | BBB/ BBB-
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	0.00%	0.00%
Sovereign Debt | UK | BB and lower
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	0.00%	0.00%
Sovereign Debt | UK | A1+/A2/SP-1
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	1.00%	0.00%
Sovereign Debt | UK | Not Rated
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	0.00%	0.00%
Sovereign Debt | Germany
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Total carrying value	$ 3,651	$ 2,222
Sovereign Debt | Germany | AAA/ AA-
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	100.00%	100.00%
Sovereign Debt | Germany | A/ A-
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	0.00%	0.00%
Sovereign Debt | Germany | BBB/ BBB-
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	0.00%	0.00%
Sovereign Debt | Germany | BB and lower
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	0.00%	0.00%
Sovereign Debt | Germany | A1+/A2/SP-1
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	0.00%	0.00%
Sovereign Debt | Germany | Not Rated
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	0.00%	0.00%
Sovereign Debt | France
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Total carrying value	$ 1,852	$ 1,697
Sovereign Debt | France | AAA/ AA-
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	100.00%	100.00%
Sovereign Debt | France | A/ A-
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	0.00%	0.00%
Sovereign Debt | France | BBB/ BBB-
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	0.00%	0.00%
Sovereign Debt | France | BB and lower
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	0.00%	0.00%
Sovereign Debt | France | A1+/A2/SP-1
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	0.00%	0.00%
Sovereign Debt | France | Not Rated
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	0.00%	0.00%
Sovereign Debt | Italy
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Total carrying value	$ 1,536	$ 2,010
Sovereign Debt | Italy | AAA/ AA-
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	0.00%	0.00%
Sovereign Debt | Italy | A/ A-
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	0.00%	0.00%
Sovereign Debt | Italy | BBB/ BBB-
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	100.00%	100.00%
Sovereign Debt | Italy | BB and lower
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	0.00%	0.00%
Sovereign Debt | Italy | A1+/A2/SP-1
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	0.00%	0.00%
Sovereign Debt | Italy | Not Rated
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	0.00%	0.00%
Sovereign Debt | Singapore
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Total carrying value	$ 1,102	$ 984
Sovereign Debt | Singapore | AAA/ AA-
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	100.00%	100.00%
Sovereign Debt | Singapore | A/ A-
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	0.00%	0.00%
Sovereign Debt | Singapore | BBB/ BBB-
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	0.00%	0.00%
Sovereign Debt | Singapore | BB and lower
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	0.00%	0.00%
Sovereign Debt | Singapore | A1+/A2/SP-1
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	0.00%	0.00%
Sovereign Debt | Singapore | Not Rated
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	0.00%	0.00%
Sovereign Debt | Spain
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Total carrying value	$ 998	$ 1,920
Sovereign Debt | Spain | AAA/ AA-
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	0.00%	0.00%
Sovereign Debt | Spain | A/ A-
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	9.00%	5.00%
Sovereign Debt | Spain | BBB/ BBB-
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	91.00%	95.00%
Sovereign Debt | Spain | BB and lower
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	0.00%	0.00%
Sovereign Debt | Spain | A1+/A2/SP-1
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	0.00%	0.00%
Sovereign Debt | Spain | Not Rated
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	0.00%	0.00%
Sovereign Debt | Hong Kong
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Total carrying value	$ 568	$ 29
Sovereign Debt | Hong Kong | AAA/ AA-
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	100.00%	100.00%
Sovereign Debt | Hong Kong | A/ A-
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	0.00%	0.00%
Sovereign Debt | Hong Kong | BBB/ BBB-
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	0.00%	0.00%
Sovereign Debt | Hong Kong | BB and lower
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	0.00%	0.00%
Sovereign Debt | Hong Kong | A1+/A2/SP-1
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	0.00%	0.00%
Sovereign Debt | Hong Kong | Not Rated
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	0.00%	0.00%
Sovereign Debt | Japan
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Total carrying value	$ 296	$ 408
Sovereign Debt | Japan | AAA/ AA-
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	0.00%	0.00%
Sovereign Debt | Japan | A/ A-
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	100.00%	100.00%
Sovereign Debt | Japan | BBB/ BBB-
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	0.00%	0.00%
Sovereign Debt | Japan | BB and lower
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	0.00%	0.00%
Sovereign Debt | Japan | A1+/A2/SP-1
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	0.00%	0.00%
Sovereign Debt | Japan | Not Rated
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	0.00%	0.00%
Sovereign Debt | Netherlands
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Total carrying value	$ 340	$ 491
Sovereign Debt | Netherlands | AAA/ AA-
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	100.00%	100.00%
Sovereign Debt | Netherlands | A/ A-
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	0.00%	0.00%
Sovereign Debt | Netherlands | BBB/ BBB-
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	0.00%	0.00%
Sovereign Debt | Netherlands | BB and lower
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	0.00%	0.00%
Sovereign Debt | Netherlands | A1+/A2/SP-1
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	0.00%	0.00%
Sovereign Debt | Netherlands | Not Rated
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	0.00%	0.00%
Sovereign Debt | Austria
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Total carrying value	$ 306	$ 256
Sovereign Debt | Austria | AAA/ AA-
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	100.00%	100.00%
Sovereign Debt | Austria | A/ A-
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	0.00%	0.00%
Sovereign Debt | Austria | BBB/ BBB-
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	0.00%	0.00%
Sovereign Debt | Austria | BB and lower
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	0.00%	0.00%
Sovereign Debt | Austria | A1+/A2/SP-1
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	0.00%	0.00%
Sovereign Debt | Austria | Not Rated
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	0.00%	0.00%
Sovereign Debt | Ireland
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Total carrying value	$ 235	$ 252
Sovereign Debt | Ireland | AAA/ AA-
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	0.00%	0.00%
Sovereign Debt | Ireland | A/ A-
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	100.00%	100.00%
Sovereign Debt | Ireland | BBB/ BBB-
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	0.00%	0.00%
Sovereign Debt | Ireland | BB and lower
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	0.00%	0.00%
Sovereign Debt | Ireland | A1+/A2/SP-1
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	0.00%	0.00%
Sovereign Debt | Ireland | Not Rated
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	0.00%	0.00%
Sovereign Debt | Other
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Total carrying value	$ 331	$ 461
Sovereign Debt | Other | AAA/ AA-
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	60.00%	73.00%
Sovereign Debt | Other | A/ A-
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	0.00%	0.00%
Sovereign Debt | Other | BBB/ BBB-
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	0.00%	0.00%
Sovereign Debt | Other | BB and lower
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	40.00%	27.00%
Sovereign Debt | Other | A1+/A2/SP-1
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	0.00%	0.00%
Sovereign Debt | Other | Not Rated
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	0.00%	0.00%
Foreign government agencies
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Total carrying value	$ 2,679	$ 4,135
Foreign government agencies | AAA/ AA-
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	92.00%	95.00%
Foreign government agencies | A/ A-
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	8.00%	5.00%
Foreign government agencies | BBB/ BBB-
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	0.00%	0.00%
Foreign government agencies | BB and lower
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	0.00%	0.00%
Foreign government agencies | A1+/A2/SP-1
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	0.00%	0.00%
Foreign government agencies | Not Rated
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	0.00%	0.00%
Foreign government agencies | Canada
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Total carrying value	$ 572	$ 511
Foreign government agencies | Canada | AAA/ AA-
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	78.00%	75.00%
Foreign government agencies | Canada | A/ A-
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	22.00%	25.00%
Foreign government agencies | Canada | BBB/ BBB-
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	0.00%	0.00%
Foreign government agencies | Canada | BB and lower
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	0.00%	0.00%
Foreign government agencies | Canada | A1+/A2/SP-1
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	0.00%	0.00%
Foreign government agencies | Canada | Not Rated
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	0.00%	0.00%
Foreign government agencies | Norway
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Total carrying value	$ 270	$ 273
Foreign government agencies | Norway | AAA/ AA-
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	100.00%	100.00%
Foreign government agencies | Norway | A/ A-
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	0.00%	0.00%
Foreign government agencies | Norway | BBB/ BBB-
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	0.00%	0.00%
Foreign government agencies | Norway | BB and lower
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	0.00%	0.00%
Foreign government agencies | Norway | A1+/A2/SP-1
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	0.00%	0.00%
Foreign government agencies | Norway | Not Rated
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	0.00%	0.00%
Foreign government agencies | Germany
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Total carrying value	$ 0	$ 1,473
Foreign government agencies | Germany | AAA/ AA-
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	0.00%	100.00%
Foreign government agencies | Germany | A/ A-
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	0.00%	0.00%
Foreign government agencies | Germany | BBB/ BBB-
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	0.00%	0.00%
Foreign government agencies | Germany | BB and lower
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	0.00%	0.00%
Foreign government agencies | Germany | A1+/A2/SP-1
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	0.00%	0.00%
Foreign government agencies | Germany | Not Rated
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	0.00%	0.00%
Foreign government agencies | France
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Total carrying value	$ 277	$ 305
Foreign government agencies | France | AAA/ AA-
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	100.00%	100.00%
Foreign government agencies | France | A/ A-
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	0.00%	0.00%
Foreign government agencies | France | BBB/ BBB-
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	0.00%	0.00%
Foreign government agencies | France | BB and lower
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	0.00%	0.00%
Foreign government agencies | France | A1+/A2/SP-1
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	0.00%	0.00%
Foreign government agencies | France | Not Rated
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	0.00%	0.00%
Foreign government agencies | Sweden
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Total carrying value	$ 253	$ 281
Foreign government agencies | Sweden | AAA/ AA-
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	100.00%	100.00%
Foreign government agencies | Sweden | A/ A-
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	0.00%	0.00%
Foreign government agencies | Sweden | BBB/ BBB-
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	0.00%	0.00%
Foreign government agencies | Sweden | BB and lower
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	0.00%	0.00%
Foreign government agencies | Sweden | A1+/A2/SP-1
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	0.00%	0.00%
Foreign government agencies | Sweden | Not Rated
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	0.00%	0.00%
Foreign government agencies | Finland
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Total carrying value	$ 205	$ 225
Foreign government agencies | Finland | AAA/ AA-
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	100.00%	100.00%
Foreign government agencies | Finland | A/ A-
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	0.00%	0.00%
Foreign government agencies | Finland | BBB/ BBB-
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	0.00%	0.00%
Foreign government agencies | Finland | BB and lower
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	0.00%	0.00%
Foreign government agencies | Finland | A1+/A2/SP-1
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	0.00%	0.00%
Foreign government agencies | Finland | Not Rated
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	0.00%	0.00%
Foreign government agencies | Netherlands
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Total carrying value	$ 834	$ 847
Foreign government agencies | Netherlands | AAA/ AA-
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	100.00%	100.00%
Foreign government agencies | Netherlands | A/ A-
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	0.00%	0.00%
Foreign government agencies | Netherlands | BBB/ BBB-
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	0.00%	0.00%
Foreign government agencies | Netherlands | BB and lower
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	0.00%	0.00%
Foreign government agencies | Netherlands | A1+/A2/SP-1
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	0.00%	0.00%
Foreign government agencies | Netherlands | Not Rated
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	0.00%	0.00%
Foreign government agencies | Other
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Total carrying value	$ 268	$ 220
Foreign government agencies | Other | AAA/ AA-
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	64.00%	55.00%
Foreign government agencies | Other | A/ A-
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	36.00%	45.00%
Foreign government agencies | Other | BBB/ BBB-
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	0.00%	0.00%
Foreign government agencies | Other | BB and lower
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	0.00%	0.00%
Foreign government agencies | Other | A1+/A2/SP-1
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	0.00%	0.00%
Foreign government agencies | Other | Not Rated
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Ratings	0.00%	0.00%
Sovereign debt/sovereign guaranteed | Sovereign debt/sovereign guaranteed | Brazil | Carrying amount
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Total carrying value	$ 134	$ 125