Compensation and Benefit Plans (Stock Option Activity) (Details) - Stock options $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2017 USD ($) $ / shares shares
Stock options
Beginning balance (number of options) | shares	11,544,501
Grants (number of options) | shares	1,359,599
Expired (number of options) | shares	0
Forfeited (number of options) | shares	(163,449)
Exercised (number of options) | shares	(4,918,086)
Ending balance (number of options) | shares	7,822,565
Vested and expected to vest (number of options) | shares	7,740,798
Exercisable (number of options) | shares	4,241,658
Exercise Price
Beginning balance, weighted average exercise price (dollars per share) | $ / shares	$ 50.26
Granted, weighted average exercise price (dollars per share) | $ / shares	79.23
Expired, weighted average exercise price (dollars per share) | $ / shares	0.00
Forfeited, weighted average exercise price (dollars per share) | $ / shares	69.76
Exercised, weighted average exercise price (dollars per share) | $ / shares	43.77
Ending balance, weighted average exercise price (dollars per share) | $ / shares	58.98
Vested and expected to vest, weighted average exercise price (dollars per share) | $ / shares	58.81
Exercisable, weighted average exercise price (dollars per share) | $ / shares	$ 50.48
Remaining Contractual Term (Years)
Outstanding at December 31, 2016 (term)	6 years 4 months 13 days
Vested and expected to vest at December 31, 2016 (term)	6 years 4 months 6 days
Exercisable at December 31, 2016 (term)	5 years 1 month 2 days
Aggregate Intrinsic Value (in millions)
Vested and expected to vest at December 31, 2017 | $	$ 62
Exercisable at December 31, 2017 | $	$ 58
SCE
Stock options
Beginning balance (number of options) | shares	4,727,416
Grants (number of options) | shares	699,538
Expired (number of options) | shares	0
Forfeited (number of options) | shares	(77,165)
Exercised (number of options) | shares	(987,161)
Transfers, net (number of options) | shares	83,074
Ending balance (number of options) | shares	4,445,702
Vested and expected to vest (number of options) | shares	4,402,254
Exercisable (number of options) | shares	2,555,160
Exercise Price
Beginning balance, weighted average exercise price (dollars per share) | $ / shares	$ 51.81
Granted, weighted average exercise price (dollars per share) | $ / shares	79.12
Expired, weighted average exercise price (dollars per share) | $ / shares	0.00
Forfeited, weighted average exercise price (dollars per share) | $ / shares	66.27
Exercised, weighted average exercise price (dollars per share) | $ / shares	48.63
Transfers, net, weighted average exercise price (dollars per share) | $ / shares	46.47
Ending balance, weighted average exercise price (dollars per share) | $ / shares	56.46
Vested and expected to vest, weighted average exercise price (dollars per share) | $ / shares	56.28
Exercisable, weighted average exercise price (dollars per share) | $ / shares	$ 46.94
Remaining Contractual Term (Years)
Outstanding at December 31, 2016 (term)	5 years 11 months 27 days
Vested and expected to vest at December 31, 2016 (term)	5 years 11 months 16 days
Exercisable at December 31, 2016 (term)	4 years 6 months 7 days
Aggregate Intrinsic Value (in millions)
Vested and expected to vest at December 31, 2017 | $	$ 45
Exercisable at December 31, 2017 | $	$ 43