Income Taxes Operating Loss and Tax Credit Carryforwards, United States, By Expiration Dates (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2013
2014 through 2018 [Member]
Operating Loss and Tax Credit Carry Forward [Line Items]
United States federal income tax loss carryforwards	$ 1
United States federal income tax credit carryforwards	3
2019 through 2023 [Member]
Operating Loss and Tax Credit Carry Forward [Line Items]
United States federal income tax loss carryforwards	0
United States federal income tax credit carryforwards	70
2024 through 2028 [Member]
Operating Loss and Tax Credit Carry Forward [Line Items]
United States federal income tax loss carryforwards	0
United States federal income tax credit carryforwards	0
2029 through 2033 [Member]
Operating Loss and Tax Credit Carry Forward [Line Items]
United States federal income tax loss carryforwards	0
United States federal income tax credit carryforwards	69
Not subject to expiration [Member]
Operating Loss and Tax Credit Carry Forward [Line Items]
United States federal income tax loss carryforwards	0
United States federal income tax credit carryforwards	19
Valuation allowance [Member]
Operating Loss and Tax Credit Carry Forward [Line Items]
United States federal income tax loss carryforwards	0
United States federal income tax credit carryforwards	$ (51)