Employee Benefit Plans (Fair values of pension and post retirement plan assets by asset category) (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Total recorded at fair value		$ 7,016	$ 6,166	$ 6,480
Pension Benefits | Dominion Gas Holdings, LLC
Defined Benefit Plan Disclosure [Line Items]
Total recorded at fair value		1,542	1,467	1,510
Other Postretirement Plans
Defined Benefit Plan Disclosure [Line Items]
Total recorded at fair value		1,512	1,382	1,402
Other Postretirement Plans | Dominion Gas Holdings, LLC
Defined Benefit Plan Disclosure [Line Items]
Total recorded at fair value		299	283	$ 288
Collective Bargaining Agreement | Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Total recorded at fair value		4,233	4,082
Total recorded at NAV	[1]	2,765	2,074
Pension plan assets by asset category	[2]	6,998	6,156
Pending sales of securities		46	112
Net accrued income		19	16
Pending purchases of securities		47	118
Collective Bargaining Agreement | Pension Benefits | Cash equivalents and other
Defined Benefit Plan Disclosure [Line Items]
Total recorded at fair value		14	16
Collective Bargaining Agreement | Pension Benefits | Common and preferred stocks | U.S.
Defined Benefit Plan Disclosure [Line Items]
Total recorded at fair value		1,705	1,736
Collective Bargaining Agreement | Pension Benefits | Common and preferred stocks | International
Defined Benefit Plan Disclosure [Line Items]
Total recorded at fair value		928	786
Collective Bargaining Agreement | Pension Benefits | Insurance contracts
Defined Benefit Plan Disclosure [Line Items]
Total recorded at fair value		334	330
Collective Bargaining Agreement | Pension Benefits | Corporate debt instruments
Defined Benefit Plan Disclosure [Line Items]
Total recorded at fair value		717	739
Collective Bargaining Agreement | Pension Benefits | Government securities
Defined Benefit Plan Disclosure [Line Items]
Total recorded at fair value		535	475
Collective Bargaining Agreement | Pension Benefits | Common/collective trust funds
Defined Benefit Plan Disclosure [Line Items]
Total recorded at NAV	[1],[3]	1,960	1,200
Collective Bargaining Agreement | Pension Benefits | Common/collective trust funds | Northern Trust Collective Short Term Investment Fund
Defined Benefit Plan Disclosure [Line Items]
Total recorded at NAV		167	125
Collective Bargaining Agreement | Pension Benefits | Real estate funds
Defined Benefit Plan Disclosure [Line Items]
Total recorded at NAV	[1]	121	153
Collective Bargaining Agreement | Pension Benefits | Private equity funds
Defined Benefit Plan Disclosure [Line Items]
Total recorded at NAV	[3]	506	465
Collective Bargaining Agreement | Pension Benefits | Debt funds
Defined Benefit Plan Disclosure [Line Items]
Total recorded at NAV	[3]	153	170
Collective Bargaining Agreement | Pension Benefits | Hedge funds
Defined Benefit Plan Disclosure [Line Items]
Total recorded at NAV	[1]	25	86
Collective Bargaining Agreement | Pension Benefits | Level 1
Defined Benefit Plan Disclosure [Line Items]
Total recorded at fair value		2,693	2,667
Collective Bargaining Agreement | Pension Benefits | Level 1 | Cash equivalents and other
Defined Benefit Plan Disclosure [Line Items]
Total recorded at fair value		12	16
Collective Bargaining Agreement | Pension Benefits | Level 1 | Common and preferred stocks | U.S.
Defined Benefit Plan Disclosure [Line Items]
Total recorded at fair value		1,705	1,736
Collective Bargaining Agreement | Pension Benefits | Level 1 | Common and preferred stocks | International
Defined Benefit Plan Disclosure [Line Items]
Total recorded at fair value		928	786
Collective Bargaining Agreement | Pension Benefits | Level 1 | Insurance contracts
Defined Benefit Plan Disclosure [Line Items]
Total recorded at fair value		0	0
Collective Bargaining Agreement | Pension Benefits | Level 1 | Corporate debt instruments
Defined Benefit Plan Disclosure [Line Items]
Total recorded at fair value		35	44
Collective Bargaining Agreement | Pension Benefits | Level 1 | Government securities
Defined Benefit Plan Disclosure [Line Items]
Total recorded at fair value		13	85
Collective Bargaining Agreement | Pension Benefits | Level 2
Defined Benefit Plan Disclosure [Line Items]
Total recorded at fair value		1,540	1,415
Collective Bargaining Agreement | Pension Benefits | Level 2 | Cash equivalents and other
Defined Benefit Plan Disclosure [Line Items]
Total recorded at fair value		2	0
Collective Bargaining Agreement | Pension Benefits | Level 2 | Common and preferred stocks | U.S.
Defined Benefit Plan Disclosure [Line Items]
Total recorded at fair value		0	0
Collective Bargaining Agreement | Pension Benefits | Level 2 | Common and preferred stocks | International
Defined Benefit Plan Disclosure [Line Items]
Total recorded at fair value		0	0
Collective Bargaining Agreement | Pension Benefits | Level 2 | Insurance contracts
Defined Benefit Plan Disclosure [Line Items]
Total recorded at fair value		334	330
Collective Bargaining Agreement | Pension Benefits | Level 2 | Corporate debt instruments
Defined Benefit Plan Disclosure [Line Items]
Total recorded at fair value		682	695
Collective Bargaining Agreement | Pension Benefits | Level 2 | Government securities
Defined Benefit Plan Disclosure [Line Items]
Total recorded at fair value		522	390
Collective Bargaining Agreement | Pension Benefits | Level 3
Defined Benefit Plan Disclosure [Line Items]
Total recorded at fair value		0	0
Collective Bargaining Agreement | Pension Benefits | Level 3 | Cash equivalents and other
Defined Benefit Plan Disclosure [Line Items]
Total recorded at fair value		0	0
Collective Bargaining Agreement | Pension Benefits | Level 3 | Common and preferred stocks | U.S.
Defined Benefit Plan Disclosure [Line Items]
Total recorded at fair value		0	0
Collective Bargaining Agreement | Pension Benefits | Level 3 | Common and preferred stocks | International
Defined Benefit Plan Disclosure [Line Items]
Total recorded at fair value		0	0
Collective Bargaining Agreement | Pension Benefits | Level 3 | Insurance contracts
Defined Benefit Plan Disclosure [Line Items]
Total recorded at fair value		0	0
Collective Bargaining Agreement | Pension Benefits | Level 3 | Corporate debt instruments
Defined Benefit Plan Disclosure [Line Items]
Total recorded at fair value		0	0
Collective Bargaining Agreement | Pension Benefits | Level 3 | Government securities
Defined Benefit Plan Disclosure [Line Items]
Total recorded at fair value		0	0
Collective Bargaining Agreement | Pension Benefits | Dominion Gas Holdings, LLC
Defined Benefit Plan Disclosure [Line Items]
Total recorded at fair value		930	970
Total recorded at NAV	[1]	608	494
Pension plan assets by asset category	[4]	1,538	1,464
Pending sales of securities		10	27
Net accrued income		4
Pending purchases of securities		10	28
Collective Bargaining Agreement | Pension Benefits | Dominion Gas Holdings, LLC | Cash equivalents and other
Defined Benefit Plan Disclosure [Line Items]
Total recorded at fair value		3	4
Collective Bargaining Agreement | Pension Benefits | Dominion Gas Holdings, LLC | Common and preferred stocks | U.S.
Defined Benefit Plan Disclosure [Line Items]
Total recorded at fair value		375	413
Collective Bargaining Agreement | Pension Benefits | Dominion Gas Holdings, LLC | Common and preferred stocks | International
Defined Benefit Plan Disclosure [Line Items]
Total recorded at fair value		203	187
Collective Bargaining Agreement | Pension Benefits | Dominion Gas Holdings, LLC | Insurance contracts
Defined Benefit Plan Disclosure [Line Items]
Total recorded at fair value		73	78
Collective Bargaining Agreement | Pension Benefits | Dominion Gas Holdings, LLC | Corporate debt instruments
Defined Benefit Plan Disclosure [Line Items]
Total recorded at fair value		158	175
Collective Bargaining Agreement | Pension Benefits | Dominion Gas Holdings, LLC | Government securities
Defined Benefit Plan Disclosure [Line Items]
Total recorded at fair value		118	113
Collective Bargaining Agreement | Pension Benefits | Dominion Gas Holdings, LLC | Common/collective trust funds
Defined Benefit Plan Disclosure [Line Items]
Total recorded at NAV	[1],[5]	430	286
Collective Bargaining Agreement | Pension Benefits | Dominion Gas Holdings, LLC | Common/collective trust funds | Northern Trust Collective Short Term Investment Fund
Defined Benefit Plan Disclosure [Line Items]
Total recorded at NAV		37	30
Collective Bargaining Agreement | Pension Benefits | Dominion Gas Holdings, LLC | Real estate funds
Defined Benefit Plan Disclosure [Line Items]
Total recorded at NAV	[1]	27	36
Collective Bargaining Agreement | Pension Benefits | Dominion Gas Holdings, LLC | Private equity funds
Defined Benefit Plan Disclosure [Line Items]
Total recorded at NAV	[3]	111	111
Collective Bargaining Agreement | Pension Benefits | Dominion Gas Holdings, LLC | Debt funds
Defined Benefit Plan Disclosure [Line Items]
Total recorded at NAV	[3]	34	40
Collective Bargaining Agreement | Pension Benefits | Dominion Gas Holdings, LLC | Hedge funds
Defined Benefit Plan Disclosure [Line Items]
Total recorded at NAV	[1]	6	21
Collective Bargaining Agreement | Pension Benefits | Dominion Gas Holdings, LLC | Level 1
Defined Benefit Plan Disclosure [Line Items]
Total recorded at fair value		592	634
Collective Bargaining Agreement | Pension Benefits | Dominion Gas Holdings, LLC | Level 1 | Cash equivalents and other
Defined Benefit Plan Disclosure [Line Items]
Total recorded at fair value		3	4
Collective Bargaining Agreement | Pension Benefits | Dominion Gas Holdings, LLC | Level 1 | Common and preferred stocks | U.S.
Defined Benefit Plan Disclosure [Line Items]
Total recorded at fair value		375	413
Collective Bargaining Agreement | Pension Benefits | Dominion Gas Holdings, LLC | Level 1 | Common and preferred stocks | International
Defined Benefit Plan Disclosure [Line Items]
Total recorded at fair value		203	187
Collective Bargaining Agreement | Pension Benefits | Dominion Gas Holdings, LLC | Level 1 | Insurance contracts
Defined Benefit Plan Disclosure [Line Items]
Total recorded at fair value		0	0
Collective Bargaining Agreement | Pension Benefits | Dominion Gas Holdings, LLC | Level 1 | Corporate debt instruments
Defined Benefit Plan Disclosure [Line Items]
Total recorded at fair value		8	10
Collective Bargaining Agreement | Pension Benefits | Dominion Gas Holdings, LLC | Level 1 | Government securities
Defined Benefit Plan Disclosure [Line Items]
Total recorded at fair value		3	20
Collective Bargaining Agreement | Pension Benefits | Dominion Gas Holdings, LLC | Level 2
Defined Benefit Plan Disclosure [Line Items]
Total recorded at fair value		338	336
Collective Bargaining Agreement | Pension Benefits | Dominion Gas Holdings, LLC | Level 2 | Cash equivalents and other
Defined Benefit Plan Disclosure [Line Items]
Total recorded at fair value		0	0
Collective Bargaining Agreement | Pension Benefits | Dominion Gas Holdings, LLC | Level 2 | Common and preferred stocks | U.S.
Defined Benefit Plan Disclosure [Line Items]
Total recorded at fair value		0	0
Collective Bargaining Agreement | Pension Benefits | Dominion Gas Holdings, LLC | Level 2 | Common and preferred stocks | International
Defined Benefit Plan Disclosure [Line Items]
Total recorded at fair value		0	0
Collective Bargaining Agreement | Pension Benefits | Dominion Gas Holdings, LLC | Level 2 | Insurance contracts
Defined Benefit Plan Disclosure [Line Items]
Total recorded at fair value		73	78
Collective Bargaining Agreement | Pension Benefits | Dominion Gas Holdings, LLC | Level 2 | Corporate debt instruments
Defined Benefit Plan Disclosure [Line Items]
Total recorded at fair value		150	165
Collective Bargaining Agreement | Pension Benefits | Dominion Gas Holdings, LLC | Level 2 | Government securities
Defined Benefit Plan Disclosure [Line Items]
Total recorded at fair value		115	93
Collective Bargaining Agreement | Pension Benefits | Dominion Gas Holdings, LLC | Level 3
Defined Benefit Plan Disclosure [Line Items]
Total recorded at fair value		0	0
Collective Bargaining Agreement | Pension Benefits | Dominion Gas Holdings, LLC | Level 3 | Cash equivalents and other
Defined Benefit Plan Disclosure [Line Items]
Total recorded at fair value		0	0
Collective Bargaining Agreement | Pension Benefits | Dominion Gas Holdings, LLC | Level 3 | Common and preferred stocks | U.S.
Defined Benefit Plan Disclosure [Line Items]
Total recorded at fair value		0	0
Collective Bargaining Agreement | Pension Benefits | Dominion Gas Holdings, LLC | Level 3 | Common and preferred stocks | International
Defined Benefit Plan Disclosure [Line Items]
Total recorded at fair value		0	0
Collective Bargaining Agreement | Pension Benefits | Dominion Gas Holdings, LLC | Level 3 | Insurance contracts
Defined Benefit Plan Disclosure [Line Items]
Total recorded at fair value		0	0
Collective Bargaining Agreement | Pension Benefits | Dominion Gas Holdings, LLC | Level 3 | Corporate debt instruments
Defined Benefit Plan Disclosure [Line Items]
Total recorded at fair value		0	0
Collective Bargaining Agreement | Pension Benefits | Dominion Gas Holdings, LLC | Level 3 | Government securities
Defined Benefit Plan Disclosure [Line Items]
Total recorded at fair value		0	0
Collective Bargaining Agreement | Other Postretirement Plans
Defined Benefit Plan Disclosure [Line Items]
Total recorded at fair value		808	752
Total recorded at NAV	[6]	702	630
Pension plan assets by asset category	[7]	1,510	1,382
Pending sales of securities		5
Net accrued income		2
Pending purchases of securities		5
Collective Bargaining Agreement | Other Postretirement Plans | Cash equivalents and other
Defined Benefit Plan Disclosure [Line Items]
Total recorded at fair value		2	2
Collective Bargaining Agreement | Other Postretirement Plans | Common and preferred stocks | U.S.
Defined Benefit Plan Disclosure [Line Items]
Total recorded at fair value		571	531
Collective Bargaining Agreement | Other Postretirement Plans | Common and preferred stocks | International
Defined Benefit Plan Disclosure [Line Items]
Total recorded at fair value		143	134
Collective Bargaining Agreement | Other Postretirement Plans | Insurance contracts
Defined Benefit Plan Disclosure [Line Items]
Total recorded at fair value		19	18
Collective Bargaining Agreement | Other Postretirement Plans | Corporate debt instruments
Defined Benefit Plan Disclosure [Line Items]
Total recorded at fair value		42	41
Collective Bargaining Agreement | Other Postretirement Plans | Government securities
Defined Benefit Plan Disclosure [Line Items]
Total recorded at fair value		31	26
Collective Bargaining Agreement | Other Postretirement Plans | Common/collective trust funds
Defined Benefit Plan Disclosure [Line Items]
Total recorded at NAV	[6],[8]	621	543
Collective Bargaining Agreement | Other Postretirement Plans | Common/collective trust funds | Northern Trust Collective Short Term Investment Fund
Defined Benefit Plan Disclosure [Line Items]
Total recorded at NAV		16	9
Collective Bargaining Agreement | Other Postretirement Plans | Real estate funds
Defined Benefit Plan Disclosure [Line Items]
Total recorded at NAV	[6]	9	14
Collective Bargaining Agreement | Other Postretirement Plans | Private equity funds
Defined Benefit Plan Disclosure [Line Items]
Total recorded at NAV	[6]	59	54
Collective Bargaining Agreement | Other Postretirement Plans | Debt funds
Defined Benefit Plan Disclosure [Line Items]
Total recorded at NAV	[6]	12	14
Collective Bargaining Agreement | Other Postretirement Plans | Hedge funds
Defined Benefit Plan Disclosure [Line Items]
Total recorded at NAV	[6]	1	5
Collective Bargaining Agreement | Other Postretirement Plans | Level 1
Defined Benefit Plan Disclosure [Line Items]
Total recorded at fair value		718	673
Collective Bargaining Agreement | Other Postretirement Plans | Level 1 | Cash equivalents and other
Defined Benefit Plan Disclosure [Line Items]
Total recorded at fair value		1	1
Collective Bargaining Agreement | Other Postretirement Plans | Level 1 | Common and preferred stocks | U.S.
Defined Benefit Plan Disclosure [Line Items]
Total recorded at fair value		571	531
Collective Bargaining Agreement | Other Postretirement Plans | Level 1 | Common and preferred stocks | International
Defined Benefit Plan Disclosure [Line Items]
Total recorded at fair value		143	134
Collective Bargaining Agreement | Other Postretirement Plans | Level 1 | Insurance contracts
Defined Benefit Plan Disclosure [Line Items]
Total recorded at fair value		0	0
Collective Bargaining Agreement | Other Postretirement Plans | Level 1 | Corporate debt instruments
Defined Benefit Plan Disclosure [Line Items]
Total recorded at fair value		2	3
Collective Bargaining Agreement | Other Postretirement Plans | Level 1 | Government securities
Defined Benefit Plan Disclosure [Line Items]
Total recorded at fair value		1	4
Collective Bargaining Agreement | Other Postretirement Plans | Level 2
Defined Benefit Plan Disclosure [Line Items]
Total recorded at fair value		90	79
Collective Bargaining Agreement | Other Postretirement Plans | Level 2 | Cash equivalents and other
Defined Benefit Plan Disclosure [Line Items]
Total recorded at fair value		1	1
Collective Bargaining Agreement | Other Postretirement Plans | Level 2 | Common and preferred stocks | U.S.
Defined Benefit Plan Disclosure [Line Items]
Total recorded at fair value		0
Collective Bargaining Agreement | Other Postretirement Plans | Level 2 | Common and preferred stocks | International
Defined Benefit Plan Disclosure [Line Items]
Total recorded at fair value		0
Collective Bargaining Agreement | Other Postretirement Plans | Level 2 | Insurance contracts
Defined Benefit Plan Disclosure [Line Items]
Total recorded at fair value		19	18
Collective Bargaining Agreement | Other Postretirement Plans | Level 2 | Corporate debt instruments
Defined Benefit Plan Disclosure [Line Items]
Total recorded at fair value		40	38
Collective Bargaining Agreement | Other Postretirement Plans | Level 2 | Government securities
Defined Benefit Plan Disclosure [Line Items]
Total recorded at fair value		30	22
Collective Bargaining Agreement | Other Postretirement Plans | Level 3
Defined Benefit Plan Disclosure [Line Items]
Total recorded at fair value		0	0
Collective Bargaining Agreement | Other Postretirement Plans | Level 3 | Cash equivalents and other
Defined Benefit Plan Disclosure [Line Items]
Total recorded at fair value		0	0
Collective Bargaining Agreement | Other Postretirement Plans | Level 3 | Common and preferred stocks | U.S.
Defined Benefit Plan Disclosure [Line Items]
Total recorded at fair value		0
Collective Bargaining Agreement | Other Postretirement Plans | Level 3 | Common and preferred stocks | International
Defined Benefit Plan Disclosure [Line Items]
Total recorded at fair value		0
Collective Bargaining Agreement | Other Postretirement Plans | Level 3 | Insurance contracts
Defined Benefit Plan Disclosure [Line Items]
Total recorded at fair value		0	0
Collective Bargaining Agreement | Other Postretirement Plans | Level 3 | Corporate debt instruments
Defined Benefit Plan Disclosure [Line Items]
Total recorded at fair value		0	0
Collective Bargaining Agreement | Other Postretirement Plans | Level 3 | Government securities
Defined Benefit Plan Disclosure [Line Items]
Total recorded at fair value		0	0
Collective Bargaining Agreement | Other Postretirement Plans | Dominion Gas Holdings, LLC
Defined Benefit Plan Disclosure [Line Items]
Total recorded at fair value		145	137
Total recorded at NAV	[9]	154	146
Pension plan assets by asset category		299	283
Collective Bargaining Agreement | Other Postretirement Plans | Dominion Gas Holdings, LLC | Common and preferred stocks | U.S.
Defined Benefit Plan Disclosure [Line Items]
Total recorded at fair value		121	113
Collective Bargaining Agreement | Other Postretirement Plans | Dominion Gas Holdings, LLC | Common and preferred stocks | International
Defined Benefit Plan Disclosure [Line Items]
Total recorded at fair value		24	24
Collective Bargaining Agreement | Other Postretirement Plans | Dominion Gas Holdings, LLC | Common/collective trust funds
Defined Benefit Plan Disclosure [Line Items]
Total recorded at NAV	[7],[9]	140	132
Collective Bargaining Agreement | Other Postretirement Plans | Dominion Gas Holdings, LLC | Common/collective trust funds | Northern Trust Collective Short Term Investment Fund
Defined Benefit Plan Disclosure [Line Items]
Total recorded at NAV		2	3
Collective Bargaining Agreement | Other Postretirement Plans | Dominion Gas Holdings, LLC | Real estate funds
Defined Benefit Plan Disclosure [Line Items]
Total recorded at NAV	[9]	1	2
Collective Bargaining Agreement | Other Postretirement Plans | Dominion Gas Holdings, LLC | Private equity funds
Defined Benefit Plan Disclosure [Line Items]
Total recorded at NAV	[9]	12	11
Collective Bargaining Agreement | Other Postretirement Plans | Dominion Gas Holdings, LLC | Debt funds
Defined Benefit Plan Disclosure [Line Items]
Total recorded at NAV	[9]	1	1
Collective Bargaining Agreement | Other Postretirement Plans | Dominion Gas Holdings, LLC | Level 1
Defined Benefit Plan Disclosure [Line Items]
Total recorded at fair value		145	137
Collective Bargaining Agreement | Other Postretirement Plans | Dominion Gas Holdings, LLC | Level 1 | Common and preferred stocks | U.S.
Defined Benefit Plan Disclosure [Line Items]
Total recorded at fair value		121	113
Collective Bargaining Agreement | Other Postretirement Plans | Dominion Gas Holdings, LLC | Level 1 | Common and preferred stocks | International
Defined Benefit Plan Disclosure [Line Items]
Total recorded at fair value		24	24
Collective Bargaining Agreement | Other Postretirement Plans | Dominion Gas Holdings, LLC | Level 2
Defined Benefit Plan Disclosure [Line Items]
Total recorded at fair value		0	0
Collective Bargaining Agreement | Other Postretirement Plans | Dominion Gas Holdings, LLC | Level 2 | Common and preferred stocks | U.S.
Defined Benefit Plan Disclosure [Line Items]
Total recorded at fair value		0	0
Collective Bargaining Agreement | Other Postretirement Plans | Dominion Gas Holdings, LLC | Level 2 | Common and preferred stocks | International
Defined Benefit Plan Disclosure [Line Items]
Total recorded at fair value		0	0
Collective Bargaining Agreement | Other Postretirement Plans | Dominion Gas Holdings, LLC | Level 3
Defined Benefit Plan Disclosure [Line Items]
Total recorded at fair value		0	0
Collective Bargaining Agreement | Other Postretirement Plans | Dominion Gas Holdings, LLC | Level 3 | Common and preferred stocks | U.S.
Defined Benefit Plan Disclosure [Line Items]
Total recorded at fair value		0	0
Collective Bargaining Agreement | Other Postretirement Plans | Dominion Gas Holdings, LLC | Level 3 | Common and preferred stocks | International
Defined Benefit Plan Disclosure [Line Items]
Total recorded at fair value		$ 0	$ 0

[1] These investments that are measured at fair value using the NAV per share (or its equivalent) as a practical expedient are not required to be categorized in the fair value hierarchy.

[2] Includes net assets related to pending sales of securities of $46 million, net accrued income of $19 million, and excludes net assets related to pending purchases of securities of $47 million at December 31, 2016. Includes net assets related to pending sales of securities of $112 million, net accrued income of $16 million, and excludes net assets related to pending purchases of securities of $118 million at December 31, 2015.

[3] Also included in the common collective trust funds is the Northern Trust Collective Short-Term Investment Fund, totaling $167 million and $125 million at December 31, 2016 and 2015, respectively, which is comprised of money market instruments with short-term maturities used for temporary investment. Liquidity is emphasized to provide for redemption of units on any business day. Principal preservation is also a prime objective. Admissions and withdrawals are made daily. Interest is accrued daily and distributed monthly.

[4] Includes net assets related to pending sales of securities of $10 million, net accrued income of $4 million, and excludes net assets related to pending purchases of securities of $10 million at December 31, 2016. Includes net assets related to pending sales of securities of $27 million, net accrued income of $4 million, and excludes net assets related to pending purchases of securities of $28 million at December 31, 2015.

[5] Also included in the common collective trust funds is the Northern Trust Collective Short-Term Investment Fund, totaling $37 million and $30 million at December 31, 2016 and 2015, respectively, which is comprised of money market instruments with short-term maturities used for temporary investment. Liquidity is emphasized to provide for redemption of units on any business day. Principal preservation is also a prime objective. Admissions and withdrawals are made daily. Interest is accrued daily and distributed monthly.

[6] Also included in the common collective trust funds is the Northern Trust Collective Short-Term Investment Fund, totaling $16 million and $9 million at December 31, 2016 and 2015, respectively, which is comprised of money market instruments with short-term maturities used for temporary investment. Liquidity is emphasized to provide for redemption of units on any business day. Principal preservation is also a prime objective. Admissions and withdrawals are made daily. Interest is accrued daily and distributed monthly.

[7] Includes net assets related to pending sales of securities of $5 million, net accrued income of $2 million, and excludes net assets related to pending purchases of securities of $5 million at December 31, 2016.

[8] These investments that are measured at fair value using the NAV per share (or its equivalent) as a practical expedient are not required to be categorized in the fair value hierarchy.

[9] Also included in the common collective trust funds is the Northern Trust Collective Short-Term Investment Fund, totaling $2 million and $3 million at December 31, 2016 and 2015, respectively, which is comprised of money market instruments with short-term maturities used for temporary investment. Liquidity is emphasized to provide for redemption of units on any business day. Principal preservation is also a prime objective. Admissions and withdrawals are made daily. Interest is accrued daily and distributed monthly.