Compensation and Benefit Plans (Textual) (Details) - USD ($) shares in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Assumed average equity risk premium (percent)	5.00%
Forecasted return on private equity and opportunistic investments (percent)	2.00%
Performance incentive plan award (shares)	66
Share-based compensation, shares available for grant	32
Stock options
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Stock options, expiration period, years	10 years
Stock options, vesting period, years	4 years
Volatility period	71 months	71 months	72 months
Pension Plans
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Expected contributions	$ 136
Actuarial gain (loss)	$ 125	$ 149
Discount rate (percent)	3.94%	4.18%
Permissible range of asset class weights (percent)	3.00%
Publicly traded equity investments located in the US (percent)	69.00%	63.00%
Pension Plans | US Equities
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Target plan asset allocations (percent)	29.00%
Pension Plans | Non-US Equities
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Target plan asset allocations (percent)	17.00%
Pension Plans | Fixed Income
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Target plan asset allocations (percent)	35.00%
Pension Plans | Opportunistic Alternative Investments
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Target plan asset allocations (percent)	15.00%
Pension Plans | Other Investments
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Target plan asset allocations (percent)	4.00%
Voluntary Employee Beneficiary Association (VEBA) | Non-US Equities
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Target plan asset allocations (percent)	5.00%
Voluntary Employee Beneficiary Association (VEBA) | Fixed Income
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Target plan asset allocations (percent)	85.00%
Voluntary Employee Beneficiary Association (VEBA) | Opportunistic Alternative Investments
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Target plan asset allocations (percent)	10.00%
Postretirement Benefits Other Than Pensions
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Expected contributions	$ 21
Eligibility age	55 years
Service period for eligibility (at least) (years)	10 years
Defined benefit obligation increase (decrease) during the period	$ (40)	$ (62)
Actuarial gain (loss)	110	500
Experience gains	165	300
(Loss) income from a (decrease) increase in the discount rate	$ (95)	$ 140
Discount rate (percent)	4.29%	4.55%	4.16%
Publicly traded equity investments located in the US (percent)	63.00%	71.00%
Postretirement Benefits Other Than Pensions | US Equities
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Target plan asset allocations (percent)	41.00%
Postretirement Benefits Other Than Pensions | Non-US Equities
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Target plan asset allocations (percent)	17.00%
Postretirement Benefits Other Than Pensions | Fixed Income
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Target plan asset allocations (percent)	34.00%
Postretirement Benefits Other Than Pensions | Opportunistic Alternative Investments
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Target plan asset allocations (percent)	7.00%
Postretirement Benefits Other Than Pensions | Other Investments
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Target plan asset allocations (percent)	1.00%
SCE | Pension Plans
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Expected contributions	$ 85
Actuarial gain (loss)	$ 140	$ 143
Discount rate (percent)	3.94%	4.18%
SCE | Postretirement Benefits Other Than Pensions
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined benefit obligation increase (decrease) during the period	$ (40)	$ (61)
Actuarial gain (loss)	$ 110	$ 500
Discount rate (percent)	4.29%	4.55%