Long-Term Debt Long-Term Debt (Schedule Of Early Redemption)(Details) (Details) $ in Millions	Dec. 31, 2016 USD ($)
Debt Instrument [Line Items]
Junior Subordinated Notes	$ 165
Debt Redemptions and Repurchases, Par	265
Long-term Senior notes redeemed	100
Long-Term Debt, Senior Note at 3.60% [Member]
Debt Instrument [Line Items]
Long-term Senior notes redeemed	11
Long-Term Debt, Senior Note at 4.00% [Member]
Debt Instrument [Line Items]
Long-term Senior notes redeemed	89
Junior Subordinated Notes, Coupon Rate, 3mL 2.85% [Member]
Debt Instrument [Line Items]
Junior Subordinated Notes	51
Junior Subordinated Notes, Coupon Rate, 3mL 1.90% 2.22% [Member]
Debt Instrument [Line Items]
Junior Subordinated Notes	36
Junior Subordinated Notes, Coupon Rate, 3mL 1.78% 2.29% [Member]
Debt Instrument [Line Items]
Junior Subordinated Notes	62
Junior Subordinated Notes, Coupon Rate, 3mL 3.15% 3.75% [Member]
Debt Instrument [Line Items]
Junior Subordinated Notes	8
Junior Subordinated Notes, Coupon Rate, 3mL 2.89% 3.42% [Member]
Debt Instrument [Line Items]
Junior Subordinated Notes	$ 8