Retirement Plans (Tables)

12 Months Ended

Dec. 31, 2016

Retirement Plans [Abstract]

Projected Benefit Obligations, Fair Values of Plan Assets and Amounts Recognized in the Balance Sheet

($ in millions)	2016		2015
Change in projected benefit obligation (PBO)
PBO at beginning of year	$	2,142	$	2,210
Service cost		88		55
Interest cost		122		88
Actuarial (gain)/loss		137		(88)
Benefits paid		(155)		(128)
Connecticut Acquisition transfer		-		5
CTF Acquisition PBO		1,108		-
Special termination benefits		23		-
PBO at end of year	$	3,465	$	2,142
Change in plan assets
Fair value of plan assets at beginning of year	$	1,572	$	1,673
Fair value of plan assets for the CTF operations as of acquisition date		1,120		-
Fair value of plan assets for the Connecticut Operations as of acquisition date		-		5
Actual return on plan assets		201		(40)
Employer contributions		28		62
Benefits paid		(155)		(128)
Fair value of plan assets at end of year	$	2,766	$	1,572
Funded status	$	(699)	$	(570)
Amounts recognized in the consolidated balance sheet
Pension and other postretirement benefits - current	$	-	$	(9)
Pension and other postretirement benefits - noncurrent	$	(699)	$	(561)
Accumulated other comprehensive loss	$	647	$	584

Net Periodic Benefit Cost

($ in millions)	2016		2015		2014
Components of total pension benefit cost
Service cost	$	88	$	55	$	42
Interest cost on projected benefit obligation		122		88		80
Expected return on plan assets		(168)		(129)		(99)
Amortization of unrecognized loss		40		29		20
Net periodic pension benefit cost		82		43		43
Special termination benefits		23		-		-
Total pension benefit cost	$	105	$	43	$	43

Weighted Average Asset Allocations, By Asset Category

	2016		2015
Asset category:
Equity securities	50	%	47	%
Debt securities	38	%	46	%
Alternative investments	11	%	6	%
Cash and other	1	%	1	%
Total	100	%	100	%

Expected Benefit Payments Over The Next Ten Years

($ in millions)	Amount
2017	$	375
2018		308
2019		293
2020		281
2021		271
2022-2026		1,224
Total	$	2,752

Schedule of Assumptions Used

	2016		2015		2014
Discount rate - used at year end to value obligation	4.10	%	4.50	%	4.10	%
Discount rate - used to compute annual cost	4.50	%	4.10	%	4.90	%
Expected long-term rate of return on plan assets	7.50	%	7.75	%	7.75	%
Rate of increase in compensation levels	2.50	%	2.50	%	2.50	%

Schedule of Changes in Projected benefit Obligations for OPEB

($ in millions)	2016		2015
Change in benefit obligation
Benefit obligation at beginning of year	$	626	$	727
CTF Acquisition PBO		276		-
Service cost		19		19
Interest cost		37		30
Plan participants' contributions		5		5
Actuarial (gain)/loss		(18)		(115)
Benefits paid		(23)		(25)
Connecticut Acquisition transfer		-		5
Plan change		-		(20)
Special termination benefits		3		-
Benefit obligation at end of year	$	925	$	626
Change in plan assets
Fair value of plan assets at beginning of year	$	-	$	-
Plan participants' contributions		5		5
Employer contribution		18		20
Benefits paid		(23)		(25)
Fair value of plan assets at end of year	$	-	$	-
Funded status	$	(925)	$	(626)
Amounts recognized in the consolidated balance sheet
Pension and other postretirement benefits - current	$	(23)	$	(24)
Pension and other postretirement benefits - noncurrent	$	(902)	$	(602)
Accumulated other comprehensive (gain) loss	$	(29)	$	(20)

Schedule of Net Benefit Costs For OPEB

($ in millions)	2016		2015		2014
Components of total postretirement benefit cost
Service cost	$	19	$	19	$	11
Interest cost on projected benefit obligation		37		30		22
Amortization of prior service cost /(credit)		(9)		(5)		(4)
Amortization of unrecognized loss		1		8		3
Net periodic postretirement benefit cost		48		52		32
Special termination benefits		3		-		-
Total postretirement benefit cost	$	51	$	52	$	32

Schedule of Assumptions Used for OPEB

	2016	2015	2014
Discount rate - used at year end to value obligation	4.10% - 4.30%	4.50% - 4.70%	4.10% - 4.20%
Discount rate - used to compute annual cost	4.50% - 4.70%	4.10% - 4.20%	4.90% - 5.20%

Schedule of Expected Benefit Payments for OPEB

($ in millions)	Gross Benefit		Medicare Part D Subsidy		Total
2017	$	24	$	-	$	24
2018		30		-		30
2019		38		-		38
2020		44		-		44
2021		49		-		49
2022-2026		298		1		299
Total	$	483	$	1	$	484

Net Periodic Benefit Cost Not Yet Recognized

	Pension Plan				OPEB
($ in millions)	2016		2015		2016		2015
Net actuarial loss	$	647	$	584	$	1	$	20
Prior service cost/(credit)		-		-		(30)		(40)
Total	$	647	$	584	$	(29)	$	(20)

Amounts Recognized as a Componenet of Accumulated Comprehensive Income

	Pension Plan				OPEB
($ in millions)	2016		2015		2016		2015
Accumulated other comprehensive (gain) loss at
beginning of year	$	584	$	532	$	(20)	$	119
Net actuarial gain (loss) recognized during year		(40)		(29)		(1)		(8)
Prior service (cost) credit recognized during year		-		-		9		5
Net actuarial loss (gain) occurring during year		103		81		(17)		(136)
Net amount recognized in comprehensive income
(loss) for the year		63		52		(9)		(139)
Accumulated other comprehensive (gain) loss at
end of year	$	647	$	584	$	(29)	$	(20)