Investments - (Tables)

12 Months Ended

Mar. 31, 2026

Disclosure Of Investments Other Than Investments Accounted For Using Equity Method [Abstract]

Schedule of Carrying Value of Investments

The carrying value of investments are as follows:


(Dollars in millions)
		As of
		March 31, 2026				March 31, 2025
Current investments
Amortized cost:
Quoted debt securities		11					20

Fair value through profit and loss:
Mutual funds		251				229

Fair Value through other comprehensive income:
Quoted debt securities		132				375
Certificates of deposit		844					410
Commercial Paper		127					426
			1,365				1,460
Non-Current investments
Amortized cost:
Quoted debt securities		46				173

Fair value through other comprehensive income:
Quoted debt securities		790					1,014
Quoted equity securities		6					7
Unquoted equity and preference securities		66				20

Fair value through profit and loss:
Target maturity fund units			—				54
Unquoted equity and preference securities		6					3
Others		28				23
			942				1,294
Total Investments			2,307				2,754
Investment carried at amortized cost			57				193
Investments carried at fair value through other comprehensive income			1,965				2,252
Investments carried at fair value through profit and loss			285				309

Note: Uncalled capital commitments outstanding as of March 31, 2026, and March 31, 2025, was $10 million and $14 million, respectively.

Schedule of Amounts Recorded in Other Comprehensive Income

Details of amounts recorded in other comprehensive income:


(Dollars in millions)
Net gain / (loss) on		Year ended March 31, 2026
		Gross				Tax				Net
Certificates of deposit, Commercial papers and Quoted debt securities			(3	)			1				(2	)
Equity and preference securities			49				(7	)			42


(Dollars in millions)
Net gain / (loss) on		Year ended March 31, 2025
		Gross				Tax				Net
Quoted debt securities			26				(3	)			23
Certificates of deposit and Commercial papers			1				—				1
Equity and preference securities			2				—				2


(Dollars in millions)
Net gain / (loss) on		Year ended March 31, 2024
		Gross				Tax				Net
Quoted debt securities			19				(2	)			17
Equity and preference securities			1				1				2

Schedule of Method of Fair Valuation

Method of fair valuation:


(Dollars in millions)
Class of investment		Method		Fair value
				As of March 31
				2026				2025
Mutual fund units- carried at Fair value through profit or loss		Quoted price			251				229
Target maturity fund units- carried at Fair value through profit or loss		Quoted price			—				54
Quoted debt securities- carried at amortized cost		Quoted price and market observable inputs			59				213
Quoted debt securities- carried at Fair value through other comprehensive income		Quoted price and market observable inputs			922				1,389
Commercial Paper- carried at Fair value through other comprehensive income		Market observable inputs			127				426
Certificate of deposits- carried at Fair value through other comprehensive income		Market observable inputs			844				410
Unquoted equity and preference securities - carried at fair value through profit or loss		Discounted cash flows method, Market multiples method, Option pricing model			6				3
Unquoted equity and preference securities- carried at fair value through other comprehensive income		Discounted cash flows method, Market multiples method, Option pricing model			66				20
Quoted equity securities - carried at fair value through other comprehensive income		Quoted price			6				7
Others - carried at fair value through profit or loss		Discounted cash flows method, Market multiples method, Option pricing model			28				23
					2,309				2,774

Note: Certain quoted investments are classified as Level 2 in the absence of active market for such investments.