Debt, Banking Arrangements, and Leases (Tables)

12 Months Ended

Dec. 31, 2016

Debt Disclosure [Abstract]

Schedule of Long-term Debt Instruments [Table Text Block]

Long-Term Debt

	December 31,
	2016		2015
	(Millions)
Unsecured:
Transco:
6.4% Notes due 2016 (1)	$	—	$	200
6.05% Notes due 2018	250		250
7.08% Debentures due 2026	8		8
7.25% Debentures due 2026	200		200
7.85% Notes due 2026	1,000		—
5.4% Notes due 2041	375		375
4.45% Notes due 2042	400		400
Northwest Pipeline:
7% Notes due 2016	—		175
5.95% Notes due 2017	185		185
6.05% Notes due 2018	250		250
7.125% Debentures due 2025	85		85
WPZ:
7.25% Notes due 2017	600		600
5.25% Notes due 2020	1,500		1,500
4.125% Notes due 2020	600		600
4% Notes due 2021	500		500
3.6% Notes due 2022	1,250		1,250
3.35% Notes due 2022	750		750
6.125% Notes due 2022	750		750
4.5% Notes due 2023	600		600
4.875% Notes due 2023	1,400		1,400
4.3% Notes due 2024	1,000		1,000
4.875% Notes due 2024	750		750
3.9% Notes due 2025	750		750
4% Notes due 2025	750		750
6.3% Notes due 2040	1,250		1,250
5.8% Notes due 2043	400		400
5.4% Notes due 2044	500		500
4.9% Notes due 2045	500		500
5.1% Notes due 2045	1,000		1,000
Term Loan, variable interest rate, due 2018	850		850
Credit facility loans	—		1,310
WMB:
7.875% Notes due 2021	371		371
3.7% Notes due 2023	850		850
4.55% Notes due 2024	1,250		1,250
7.5% Debentures due 2031	339		339

	December 31,
	2016			2015
	(Millions)
7.75% Notes due 2031	252			252
8.75% Notes due 2032	445			445
5.75% Notes due 2044	650			650
Various — 5.5% to 10.25% Notes and Debentures due 2019 to 2033	55			55
Credit facility loans	775			650
Capital lease obligations	—			1
Debt issuance costs	(119		)	(123		)
Net unamortized debt premium (discount)	88			110
Total long-term debt, including current portion	23,409			23,988
Long-term debt due within one year	(785		)	(176		)
Long-term debt	$	22,624		$	23,812

___________

(1) Presented as long-term debt at December 31, 2015, due to Transco’s intent and ability to refinance.

Schedule of Maturities of Long-term Debt [Table Text Block]

The following table presents aggregate minimum maturities of long-term debt, excluding net unamortized debt premium (discount), debt issuance costs, and capital lease obligations, for each of the next five years:

	December 31, 2016
	(Millions)
2017	$	785
2018	1,350
2019	32
2020	2,896
2021	871

Schedule of Line of Credit Facilities [Table Text Block]

Credit Facilities

	December 31, 2016
	Available		Outstanding
	(Millions)
WMB
Long-term credit facility	$	1,500	$	775
Letters of credit under certain bilateral bank agreements			13
WPZ
Long-term credit facility (1)	3,500		—
Letters of credit under certain bilateral bank agreements			1

________________

(1) In managing our available liquidity, we do not expect a maximum outstanding amount in excess of the capacity of our credit facility inclusive of any outstanding amounts under our commercial paper program.

Schedule of Future Minimum Rental Payments for Operating Leases [Table Text Block]

The future minimum annual rentals under noncancelable operating leases, are payable as follows:

	December 31, 2016
	(Millions)
2017	$	62
2018	58
2019	51
2020	46
2021	35
Thereafter	90
Total	$	342