
	Principal amount				Carrying amount
	September 30,		December 31,		September 30,		December 31,
	2021		2020		2021		2020
6.375% Senior Notes due December 2021	$	38	$	38	$	38	$	38
5.52% Senior Secured Notes due May 2022		42		111		42		111
3.80% Senior Notes due October 2022		27		27		27		27
0.50% Exchangeable Senior Bonds due January 2023		140		463		140		462
5.375% Senior Secured Notes due May 2023		338		364		336		360
5.875% Senior Secured Notes due January 2024		462		585		457		577
7.75% Senior Secured Notes due October 2024		330		360		325		354
6.25% Senior Secured Notes due December 2024		344		375		339		369
6.125% Senior Secured Notes due August 2025		402		468		396		461
7.25% Senior Notes due November 2025		411		411		406		405
4.00% Senior Guaranteed Exchangeable Bonds due December 2025		294		—		263		—
7.50% Senior Notes due January 2026		569		569		565		565
2.50% Senior Guaranteed Exchangeable Bonds due January 2027		238		238		271		277
11.50% Senior Guaranteed Notes due January 2027		687		687		1,078		1,139
6.875% Senior Secured Notes due February 2027		550		550		544		542
8.00% Senior Notes due February 2027		612		612		607		606
7.45% Notes due April 2027		52		52		52		51
8.00% Debentures due April 2027		22		22		22		22
7.00% Notes due June 2028		261		261		265		266
7.50% Notes due April 2031		396		396		394		394
6.80% Senior Notes due March 2038		610		610		605		605
7.35% Senior Notes due December 2041		177		177		176		176
Total debt		7,002		7,376		7,348		7,807

Less debt due within one year
6.375% Senior Notes due December 2021		38		38		38		38
5.52% Senior Secured Notes due May 2022		42		93		42		92
5.375% Senior Secured Notes due May 2023		63		47		62		46
5.875% Senior Secured Notes due January 2024		110		83		107		80
7.75% Senior Secured Notes due October 2024		60		60		58		58
6.25% Senior Secured Notes due December 2024		62		62		61		60
6.125% Senior Secured Notes due August 2025		66		66		64		64
2.50% Senior Guaranteed Exchangeable Bonds due January 2027		—		—		6		6
11.50% Senior Guaranteed Notes due January 2027		—		—		70		61
6.875% Senior Secured Notes due February 2027		69		—		67		—
Total debt due within one year		510		449		575		505
Total long-term debt	$	6,492	$	6,927	$	6,773	$	7,302


	Nine months ended September 30,
	2021						2020
	Exchanged		Repurchased		Total		Exchanged		Redeemed		Repurchased		Total
6.50% Senior Notes due November 2020	$	—	$	—	$	—	$	—	$	—	$	15	$	15
6.375% Senior Notes due December 2021		—		—		—		37		—		68		105
3.80% Senior Notes due October 2022		—		—		—		136		—		16		152
0.50% Exchangeable Senior Bonds due January 2023		323		—		323		397		—		4		401
5.375% Senior Secured Notes due May 2023		—		10		10		—		—		21		21
9.00% Senior Notes due July 2023		—		—		—		—		714		—		714
5.875% Senior Secured Notes due January 2024		—		41		41		—		—		—		—
7.25% Senior Notes due November 2025		—		—		—		207		—		—		207
7.50% Senior Notes due January 2026		—		—		—		181		—		—		181
8.00% Senior Notes due February 2027		—		—		—		138		—		—		138
7.45% Notes due April 2027		—		—		—		35		—		—		35
8.00% Debentures due April 2027		—		—		—		35		—		—		35
7.00% Notes due June 2028		—		—		—		39		—		—		39
7.50% Notes due April 2031		—		—		—		192		—		—		192
6.80% Senior Notes due March 2038		—		—		—		390		—		—		390
7.35% Senior Notes due December 2041		—		—		—		123		—		—		123
Aggregate principal amount restructured or retired	$	323	$	51	$	374	$	1,910	$	714	$	124	$	2,748

Aggregate cash payment	$	11	$	51	$	62	$	9	$	767	$	91	$	867
Aggregate principal amount of debt issued in exchanges	$	294	$	—	$	294	$	925	$	—	$	—	$	925
Aggregate net gain, three-month period	$	—	$	—	$	—	$	428	$	—	$	21	$	449
Aggregate net gain (loss), nine-month period	$	51	$	—	$	51	$	428	$	(65)	$	33	$	396

Schedule of debt

Exchange terms—At September 30, 2021, the (a) current exchange rates, expressed as the number of Transocean Ltd. shares per $1,000 note, (b) implied exchange prices per Transocean Ltd. share and (c) aggregate shares, expressed in millions, issuable upon exchange of our exchangeable bonds were as follows:


			Implied
	Exchange		exchange		Shares
	rate		price		issuable
0.50% Exchangeable Senior Bonds due January 2023		97.29756	$	10.28		13.6
4.00% Senior Guaranteed Exchangeable Bonds due December 2025		190.47620		5.25		56.0
2.50% Senior Guaranteed Exchangeable Bonds due January 2027		162.16260		6.17		38.6

Effective interest rates and fair values—At September 30, 2021, the effective interest rates and estimated fair values of our exchangeable bonds were as follows (in millions, except effective interest rates):


	Effective		Fair
	interest rate		value
0.50% Exchangeable Senior Bonds due January 2023		0.5%	$	119
4.00% Senior Guaranteed Exchangeable Bonds due December 2025		6.9%		317
2.50% Senior Guaranteed Exchangeable Bonds due January 2027		0.0%		233