Debt, Banking Arrangements, and Leases (Tables)

12 Months Ended

Dec. 31, 2015

Debt Disclosure [Abstract]

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

Long-Term Debt

	December 31,
	2015		2014
	(Millions)
Unsecured:
Transco:
6.4% Notes due 2016 (2)	$	200	$	200
6.05% Notes due 2018	250		250
7.08% Debentures due 2026	8		8
7.25% Debentures due 2026	200		200
5.4% Notes due 2041	375		375
4.45% Notes due 2042	400		400
Northwest Pipeline:
7% Notes due 2016	175		175
5.95% Notes due 2017	185		185
6.05% Notes due 2018	250		250
7.125% Debentures due 2025	85		85
WPZ:
3.8% Notes due 2015 (1)	—		750
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
5.875% Notes due 2021	—		750
3.6% Notes due 2022	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
4.0% Notes due 2025	750		—

	December 31,
	2015			2014
	(Millions)
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			—
Term Loan, variable interest rate, due 2018	850			—
Credit facility loans	1,310			640
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
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	650			370
Capital lease obligations	1			5
Debt issuance costs	(123		)	(108		)
Net unamortized debt premium (discount)	110			187
Total long-term debt, including current portion	23,988			20,784
Long-term debt due within one year	(176		)	(4		)
Long-term debt	$	23,812		$	20,780

___________

(1) Presented as long-term debt at December 31, 2014, due to WPZ's intent and ability to refinance.

(2) 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, 2015
	(Millions)
2016	$	175
2017	785
2018	1,350
2019	32
2020	2,121

Schedule of Line of Credit Facilities [Table Text Block]

Credit Facilities

	December 31, 2015
	Available		Outstanding
	(Millions)
WMB
Long-term credit facility	$	1,500	$	650
Letters of credit under certain bilateral bank agreements			14
WPZ
Long-term credit facility (1)	3,500		1,310
Letters of credit under certain bilateral bank agreements			2
Short-term credit facility	150		—

________________

(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, 2015
	(Millions)
2016	$	86
2017	74
2018	56
2019	45
2020	39
Thereafter	119
Total	$	419